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A blown head gasket is one of the worst things that can happen to your vehicle. If you don’t get it repaired quickly, the engine can become severely damaged, which will cost huge sums of money to sort out.
One cheap and effective solution is to use a head gasket sealer. These products work quickly, provide a permanent fix, and cost just a fraction of the price of a replacement head gasket.
However, choosing the first head gasket sealer you come across can cause more problems than it solves. You need to make sure the product is suitable for your vehicle, which is why we’ve compiled this list of the best head gasket sealers on the market in 2020.

Guide to Choosing the Right Head Gasket Sealer
It’s important to choose the right head gasket sealer for your vehicle, as choosing the wrong one can cause even bigger problems, such as clogged heater cores and sticky thermostats, so be sure to read our complete guide to choosing a proper sealant. Some sealers can’t be used for both diesel and gasoline engines, and others aren’t compatible with antifreeze or coolant.
This guide includes everything you need to know about head gasket sealers. We’ll go over all of the major things to look out for so that you can pick the right product the first time around.

Pro Tip: If you suspect that you have a problem with your head gasket, try not to drive the vehicle. This will prevent further damage that may be irreversible!

How Do Head Gasket Sealers Work?
Head gasket sealers contain chemicals that seek out and plug small cracks. The immense pressure and high temperatures within the engine’s combustion chamber cause the sealer’s chemicals to react, forming a rock-solid seal that instantly stops leaks.
Head gasket sealer is added to your vehicle’s cooling system via the radiator or overflow tank. With the engine running, the sealer makes its way into every nook and cranny, plugging small holes and leaks along the way.
As the name suggests, head gasket sealers are primarily used to fix problems with blown head gaskets. However, many of these products also fix other problems with cooling systems, such as leaking radiators, water pump casings, cylinder heads, and engine blocks.
This can be immensely useful as you may not know where the leak is originating from.
Key Things to Consider When Buying Head Gasket Sealer
Don’t just buy the first head gasket sealer you come across, as it might not be the right one for your vehicle. There are three key things to consider, which we’ve listed below.
Engine Compatibility
It’s crucial to check whether the head gasket sealer is compatible with your vehicle’s engine. Most head gasket sealers are designed for use in both diesel and gasoline engines, including every option on our list, but it’s always wise to double-check before buying if you’re looking elsewhere. Some are safe to use with antifreeze, however many are not. We’ll point this out in every review.
In addition to that, some head gasket sealers cannot be mixed with your engine’s coolant. This is because many products contain a chemical called sodium silicate, which clumps up when introduced to antifreeze. If a product contains sodium silicate, chances are you’ll need to drain the coolant and flush the system before and after use.
Amount Needed
For most engines, one bottle of head gasket sealer will be enough to repair any leaks. However, for bigger engines or for multiple treatments, you may need to purchase more than one bottle.
Be aware that some products are stronger than others, so you must use the right amount to avoid causing further damage. We’ve triple checked how much you need to use depending on the size of your engine, and we’ll disclose this information in each review.
Preparation and Ease of Use
While some head gasket sealers are easy to use, others require more knowledge and effort. It may be necessary to drain the coolant from the engine and then perform a flush before using some products, and the same again once the treatment has finished.
That’s fine for DIY mechanics who know what they’re doing, but for the everyday person who doesn’t know much about engines, it might be too complicated. These people may just want to stick with a simple pour-and-go product.
Now that you know why you might want a head gasket sealer and how to choose the perfect one for you and your car, let’s get into our picks for the best products available today.

Top 8 Best Head Gasket Sealers 2020
1. Best Overall Head Gasket Sealer: Bar’s Leaks Permanent Head Gasket Fix

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Why we like it: This easy-to-use head gasket sealer by Bar’s Leaks offers exceptional value for money and is safe for all engines.
Editor’s Rating:

Quick Facts:
Contains: Sodium silicate, copper
Quantity: 1 x 24 oz bottle
Antifreeze safe: Yes
Requires drain/flush: No
Downtime: 15 minutes
Bar’s Leaks Permanent Head Gasket Fix provides a permanent solution for pesky head gasket problems. It’s suitable for use with both gasoline and diesel engines, and it can be used by absolutely anybody, as there’s no need to drain or flush the coolant. Due to its ease of use, you can be back on the road in just 15 minutes.
While it’s most effective at fixing head gaskets, this product can also repair block leaks and cracked seals – that’s useful if you’re not 100% sure of where the leak is coming from. It’ll repair small, medium, and large leaks, however it isn’t suitable if there’s coolant in the oil, or if there are bubbles present in the coolant.
Preparation and Usage
No draining or flushing is necessary with this product.
Using the product is easy; simply pour it into the radiator or overflow tank, and then let the engine idle for 15 minutes. After that, you’re free to drive your vehicle as usual!
Amount Needed
One 24 oz bottle is enough to treat most 6 and 8 cylinder engines. 4 cylinder engines will only need half a bottle.
The exact amounts to use are as follows:
½ bottle treats 1 to 1.99 gallons of cooling system capacity (4 cylinder engines)
1 bottle treats 2 to 4 gallons of cooling system capacity (6 and 8 cylinder engines)
For larger engines, use 1 bottle for every 4 gallons of cooling system capacity
Our Verdict
Easy to use, highly effective, and safe for most vehicles. This product will suit most people, however it’s not the best option for more serious leaks, and those who need to plug major holes should look towards a premium product like the Bar’s Leaks Blown Head Gasket Repair instead.

Pros
Offers great value for money
Simple enough for anybody to use
Just 15 minutes downtime
One bottle treats 4, 6, and 8 cylinder engines
Bar’s Leaks is a well-known brand

Cons
Not suitable for major issues

2. Best Premium Head Gasket Sealer: Bar’s Leaks Blown Head Gasket Repair

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Why we like it: This is one of the strongest head gasket repair products on the market, due to it creating a carbon fiber-based reinforced seal.
Editor’s Rating:

Quick Facts:
Contains: Sodium silicate, titanium dioxide, triazinetriethanol
Quantity: 1 x 33.8 fl oz bottle
Antifreeze safe: Yes
Requires drain/flush: No
Downtime: 45 minutes
Bar’s Leaks Blown Head Gasket Repair can sort out intake gaskets, cracked cylinder heads and blocks, leaking heater cores, radiator leaks, and leaking freeze and core plugs – in addition to blown head gaskets, of course.
It’s the strongest leak repair product that Bar’s Leaks has to offer, as it uses carbon fiber to help create a strong and permanent seal. This is the product to choose if you have major head gasket issues, such as bubbles in the coolant or coolant mixing with the engine oil.
Preparation and Usage
As with Bar’s Leaks’ other head gasket sealer, this product also contains antifreeze safe sodium silicate, so there’s no need to drain or flush the coolant.
All you need to do is fill the radiator or overflow tank with the required amount and then reinstall the radiator cap. Ensure that the heater is set to hot and the fan on maximum, then run the engine until normal operating temperatures are reached.
The thermostat needs to open for it to work properly, so you may have to run the engine for 30 minutes. Once done, take your vehicle for a 15-minute drive, then check for leaks.
Larger leaks may take several days to fully seal, however in most cases, the results are instant.
Amount Needed
One 33.8 oz bottle will treat engines with up to 8 cylinders. For smaller or larger engines, use the following amounts:
½ bottle for 1.5 to 2.49 gallons (4 cylinder engines)
1 bottle for 2.5 to 5 gallons (6 and 8 cylinder engines)
1 bottle for every 5 gallons in engines with a larger cooling system capacity
2 oz per quart of cooling system capacity in very small engines
Our Verdict
Bar’s Leaks Blown Head Gasket Repair is one of the strongest head gasket sealers on the market. It’ll repair more serious leaks and create a strong seal that lasts.

Pros
One of the strongest products on the market
Contains antifreeze safe sodium silicate
Reinforced with carbon fiber for a stronger seal
Repairs other leaking areas of the engine

Cons
Takes a little longer to use

3. Best Budget Head Gasket Sealer: K-SEAL Coolant Leak Repair

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Why we like it: This K-SEAL product contains microfibers that create a rock-solid seal, stopping leaks in their tracks.
Editor’s Rating:

Quick Facts:
Contains: Zinc gluconate, triazinetriethanol, sodium tetraborate, copper, aluminosilicate refractory ceramic fibers
Quantity: 1 x 8 oz bottle
Antifreeze safe: Yes
Requires drain/flush: No
Downtime: 20 minutes
K-SEAL is a brand that’s trusted by professionals all across the country. They specialize in making leak repair products, so they know their stuff. Despite the small-sized bottle and affordable price, it’s seriously potent stuff!
K-SEAL Coolant Leak Repair can fix cracks in radiators, head gaskets, water pump casings, cylinder heads, and engine blocks. No matter where your leak is, K-SEAL will seek it out and repair it. Its microfiber technology meshes together and forms a strong and permanent seal when exposed to the high temperatures and pressures inside the combustion chamber.
This product is best suited for small leaks.
Preparation and Usage
There’s no sodium silicate in K-SEAL Coolant Leak Repair, so there’s no need to drain and flush the cooling system.
This product is perfect for anybody to use, as you simply pour the contents into the radiator or overflow tank and let the engine idle for 20 minutes.
Once finished, you’re ready to drive your vehicle as normal.
Amount Needed
One 8 oz bottle is sufficient for treating all 4, 6, and 8 cylinder engines.
The exact amounts to use are as follows:
1 bottle treats up to 5 gallons of cooling system capacity (4, 6, and 8 cylinder engines)
2 bottles will be needed for engines with a larger cooling system capacity
If you need more than one 8 oz bottle, take a look at the 16 oz version of K-SEAL.
Our Verdict
A small but mighty head gasket sealer that can repair different types of leaks. As an added bonus, it’s made in the USA.

Pros
One bottle treats most engines
Quick and easy to use; just pour and go
Microfiber technology creates a strong seal
One of the cheapest products on the market
Made in the USA

Cons
Only recommended for small leaks

4. Best All-Purpose Head Gasket Sealer: K&W Permanent Head Gasket & Block Repair

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Why we like it: This permanent head gasket sealer is a great all-rounder that can repair not only head gasket leaks but also heater cores, freeze plugs, radiators, and cylinder heads.
Editor’s Rating:

Quick Facts:
Contains: Water, sodium silicate, aluminosilicate refractory ceramic fibers, copper
Quantity: 1 x 32 oz bottle
Antifreeze safe: No
Requires drain/flush: Yes
Downtime: 24+ hours
K&W Permanent Head Gasket & Block Repair sorts out engine blocks, heater cores, freeze plugs, cooling systems, radiators, and cylinder heads. As it isn’t antifreeze safe, extensive draining and flushing is required, which makes using this product a rather long-winded process.
This may be a good choice for you if you are planning to clean out the cooling system anyway. For most people, the extensive flushing is too time-consuming and hands-on, and on top of that, you’ll have to purchase extra radiator flush and antifreeze.
Preparation and Usage
Extensive draining and flushing is required, and the cooling system must be left for 24 hours to dry out after use.
This product should be added to the cooling system via the radiator. With the cap reinstalled, allow the engine to idle for 30 minutes with the heater on at maximum settings. After that, the system can be drained and left to dry. An additional flush and fresh antifreeze must be added at the end.
If this sounds too complicated or time-consuming, you may want to consider Bar’s Leaks Permanent Head Gasket Fix a quick and easy sealant instead.
Amount Needed
This product comes in a 32 oz bottle, which should be mixed with 3 quarts of water. There are no specific instructions for different sized engines, however this is enough to treat 4, 6, and 8 cylinder engines.
Use the whole bottle mixed with 3 quarts of water.
Our Verdict
Uses nanotechnology to create robust seals. Unfortunately, the entire process from start to finish is very long.

Pros
One bottle is good for most vehicles
Uses nanotechnology to seal cracks and leaks
Effective performance

Cons
Takes over 24 hours to complete process
Requires extensive flushing of the system

5. Best Bulk Head Gasket Sealer: BlueDevil Head Gasket Sealer

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Why we like it: As the go-to brand for many, a large bottle of BlueDevil’s Head Gasket Sealer does a great job at plugging leaks without clogging up the engine.
Editor’s Rating:

Quick Facts:
Contains: Sodium silicate, ethylene glycol
Quantity: 1 x 32 oz bottle
Antifreeze safe: No
Requires drain/flush: Yes
Downtime: 2 hours
BlueDevil makes a number of stop leak products, including this head gasket sealer. It’s designed to provide a permanent repair for blown head gaskets, warped or cracked cylinder heads, leaking heater cores, and leaking freeze plugs.
It’s safe to use for most vehicles, however it should not be added to the engine’s existing coolant as it can cause blockages. Having said that, there’s no solid or particulate matter included in the product, so you avoid the risk of clogging the engine (when following the instructions).
Preparation and Usage
As with most of the other head gasket sealers containing sodium silicate, this product also requires that the cooling system is drained and flushed before treatment. In addition to that, the thermostat must also be removed and the cooling system filled with water.
This product is intended for use while the engine is idling and the heater is on the maximum settings. Simply pour into the radiator slowly and allow the engine to idle for 50 minutes with the radiator cap on.
After treating the engine, there’s no need to drain or flush BlueDevil Head Gasket Sealer; it can stay in the system.
Amount Needed
BlueDevil Head Gasket Sealer comes in a 32 oz bottle, which is enough to treat engines with a cooling capacity of 4.5 gallons – that’s most 4 and 6 cylinder engines. For 8 cylinder engines, you may need to use slightly more.
The exact amounts to use for your vehicle’s specific cooling system capacity is as follows:
1 bottle = 32 oz (1 quart)
Up to 3 gallons cooling capacity: ½ quart
3 to 4.5 gallons: 1 quart
5 to 6 gallons: 1 ½ quarts
6 to 7.5 gallons: 2 quarts
5 to 9 gallons: 2 ½ quarts
Our Verdict
An effective and permanent solution. It’s slightly more expensive than some other products, and it also requires a more hands on approach.

Pros
Contains no solid or particulate matter
Permanent solution that fixes multiple problems
Made in the USA
Comes in a large bottle

Cons
Takes a couple of hours to fully treat
Requires draining and flushing before use

6. Best Head Gasket Sealer for Repairing Cracks: K&W FiberLock Head Gasket & Block Repair

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Why we like it: This head gasket sealer uses nanotechnology and Kevlar to repair even the smallest of cracks. Its Cool-X condition technology helps keep engine temperatures low.
Editor’s Rating:

Quick Facts:
Contains: Water, sodium silicate, glycol monobutyl ethers, copper, aluminum, Kevlar®
Quantity: 1 x 32 oz bottle
Antifreeze safe: Yes
Requires drain/flush: No
Downtime: 15 minutes
K&W FiberLock Head Gasket & Block Repair contains several unique leak fixing chemicals. One notable chemical is Kevlar, which is usually associated with bulletproof materials.
The product’s fibers do a great job at patching cracks, while nanotechnology seeks out and repairs even the smallest of holes. It also contains Cool-X technology, which is designed to lower engine operating temperatures, thereby protecting the head gasket from extreme heat.
It wasn’t designed, unfortunately, for anything but head gaskets, so if you’ve got other areas of concern you should check out an all-purpose sealer instead.
Preparation and Usage
Designed for everyday people, K&W’s Head Gasket & Block Repair requires no draining and flushing before or after use. Simply pour the product into the radiator, switch the heater to high, and let the engine idle for 15 minutes.
Amount Needed
K&W FiberLock Head Gasket & Block Repair comes in a 32 oz bottle, which is enough to treat up to 7.5 gallons of cooling system capacity. That is sufficient for all vehicles from 4 to 8 cylinders.
Smaller engines (4 cylinders with a cooling capacity of up to 2.5 gallons) should use just ½ a bottle
Larger systems (over 7.5 gallons cooling capacity) should use 1 bottle for every 6 gallons of cooling capacity 
Our Verdict
Very quick and easy to use, ideal for people who want to get the job done quickly. Contains a unique bunch of interesting chemicals, including Kevlar.

Pros
No draining or flushing necessary
Takes just 15 minutes from start to finish
Contains Kevlar
Protects engine from extreme temperatures

Cons
Can potentially clog radiators
Not ideal for anything other than head gaskets

7. K&W Permanent Metallic Block & Radiator Seal

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Why we like it: This inexpensive offering from K&W is ideal for DIY mechanics who don’t mind spending some extra time to get the job done properly.
Editor’s Rating:

Quick Facts:
Contains: Water, sodium silicate, cellulose, aluminosilicate refractory ceramic fibers
Quantity: 1 x 16 oz can
Antifreeze safe: No
Requires drain/flush: Yes
Downtime: 24+ hours
K&W Permanent Metallic Block & Radiator Seal provides a permanent seal for head gasket leaks and works with both gasoline and diesel engines. It is suitable for use with a variety of materials, including cast iron and aluminum blocks, and copper and bi-material heater cores.
This product is best suited for DIY mechanics due to it requiring a lot of draining and flushing before and after use. While this will make the process take longer, flushing the cooling system helps remove scale, rust, and corrosion, which is good for your engine’s longevity.
The cooling system must be left to dry for 24 hours, which might be too much downtime for some people.
Preparation and Usage
There are 7 steps to follow when using this product, which includes draining the system of coolant, performing multiple flushes, adding the product to the engine, further draining, drying out, and finally adding fresh coolant.
Amount Needed
This 16 oz can must be mixed with 3 quarts of water before use. This will be sufficient for treating all regular sized engines, regardless of the cooling system capacity.
Our Verdict
This is a slightly different product from the rest as it comes in a can and must be mixed with water. It can cause solidification if added to coolant, so flushing is essential.

Pros
Provides a permanent seal
Comes in a one-size-fits-all can
Suitable for most vehicles
Popular brand

Cons
Requires extensive draining and flushing
Must wait 24 hours for the cooling system to dry out

8. Steel Seal Head Gasket Sealer

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Why we like it: Comes as a 2-pack that will be sufficient in treating 6 and 8 cylinder engines. You can’t go wrong with the 100% money-back guarantee either.
Editor’s Rating:

Quick Facts:
Contains: Proprietary ingredient, ethylene glycol
Quantity: 2 x 16 oz bottles
Antifreeze safe: No
Requires drain/flush: Yes
Downtime: 30+ minutes
Steel Seal is one of the most expensive products in our lineup, and its exact ingredients are a mystery as their proprietary formula has been withheld. Steel Seal is a lesser-known brand in the US, however, it’s more dominant in the European market.
This product is compatible with gasoline and diesel engines, however it’s not antifreeze safe, so pre- and post-use draining and flushing is necessary.
If you have a large leak, or if there are any cracks in the head, block, pumps, or hoses, then this product may not be the right one for you as it’s better for small leaks.
Preparation and Usage
Before using, check whether there’s water in your engine’s oil. If there is, you’ll need to perform an oil and filter change before using this product.
Draining the coolant and flushing the system is required both before and after using Steel Seal.
As with the other products, Steel Seal enters your engine via its cooling system. The product should be poured into the radiator or overflow tank. The engine may need to idle for 30 minutes, depending on whether the vehicle is roadworthy or not.
Amount Needed
Steel Seal Head Gasket Sealer comes as 2 bottles with 16 oz per bottle. For 6 and 8 cylinder engines, 2 bottles will be enough. 4 cylinder engines will only need to use 1 bottle.
Our Verdict
It does the job, but we feel it doesn’t provide good value for money as it’s expensive with average results, and it’s not the best for big leaks.

Pros
Well known brand in the UK and Europe
100% money-back guarantee
Comes with 2 bottles

Cons
Expensive
The exact formula is unknown
Not suitable for large leaks

Everything You Need to Know About Head Gaskets and Sealers
At the beginning of this article, we covered the three key things to consider when buying head gasket sealer. There are some additional things to think about, which include the following.
The Benefits of Using Head Gasket Sealer
To ensure you’re picking the right head gasket sealer, it’s important to consider why you need one, as they offer several benefits compared to paying for expensive repairs.
Affordability
Compared to the cost of replacing the head gasket, head gasket sealers are significantly cheaper, ultimately saving you a lot of money.
Ease of Use
Head gasket sealers have been designed for anybody to use, even if you know nothing about engines or head gaskets. This makes them the perfect solution for people with barely any mechanical knowledge: adding head gasket sealer is simple, especially when using products like Bar’s Leaks Blown Head Gasket Repair that don’t require draining or flushing before starting the process.
Little Downtime
Taking your vehicle to the mechanic usually means waiting days before being able to use it again. With most head gasket sealers, including our top overall pick, you can be back on the road in as little as 15 minutes.
Safe and Effective
Provided you use the right product for your vehicle, head gasket sealers are safe for engines and cooling systems. There’s no need to be concerned about additional problems cropping up, and in many cases the fix is permanent.
What It Fixes
If your vehicle has one or more symptoms of a blown head gasket, then the head gasket has probably failed. However, the symptoms are sometimes indicative of something else being wrong. Many head gasket sealers will also solve other problems, such as cracks in radiators, leaking water pump casings, cracked engine blocks, warped cylinder heads, and leaking heater cores.
When choosing the right product for your vehicle, be sure to take a look at what else it can fix besides just the head gasket.
Compatibility
Compatibility is vitally important, so don’t skip this. If you choose a head gasket sealer that’s not compatible with your vehicle for whatever reason, you may end up with even bigger problems, which means even bigger repair bills!
The key thing to look out for here is whether the sealer works with gasoline or diesel engines. Most good head gasket sealers are suitable for both fuel types.
It’s also important to check whether the product is antifreeze safe or not, as dumping it directly into the coolant can cause blockages within the cooling system.
Sodium silicate is one chemical people keep an eye out for, as it’s known to cause problems with antifreeze. In general, if a product contains sodium silicate, it’s likely you’ll have to drain the coolant and flush the engine both before and after use.
How Much to Use
The size of your engine and its cooling system will determine how much head gasket sealer you’ll need to use. Most bottles will be suitable for 4, 6, and 8 cylinder engines, but it’s best to check, as you don’t want to be caught short. If you have a large truck or heavy machinery, you may need to purchase multiple bottles.
In addition to that, you don’t want to overdo it by using too much. If you do use too much, you may cause damage to the engine through corrosion and blockages, which will result in even more issues that only a garage can fix.
Ease of Use
What do you know about engines? If you know nothing about head gaskets, cooling systems, and basic mechanics, you’ll be better off with one of the easier to use head gasket sealers. These are simply poured into the radiator, and there’s no need to drain or flush the coolant. With these pour-and-go head gasket sealers, you won’t need to tinker with any complicated parts of the engine.
On the other hand, if you’re a bit of a DIY mechanic, then you may want to choose a head gasket sealer that has a few more steps involved. If the thought of draining the coolant and flushing the cooling system doesn’t scare you, then it may be worth doing. It’s always good to clean out the cooling system and refill it with fresh antifreeze.
Effectiveness
How long will the repair last for? Most head gasket sealers offer a permanent solution, however the fix may not be effective if there’s extensive damage, or if the leaks are too big.
Head gasket sealers will never be as good as replacing the actual head gasket, but they’re certainly worth a try considering how cheap they are.
In many cases, these sealers keep vehicles running for many more thousands of miles, so there’s no doubt they work for repairing damaged head gaskets.
Downtime
If you can’t be without your vehicle for too long, then you’ll want a quick solution that’ll get you back on the road in minutes. Several of these head gasket sealers take under half an hour to work, so these will be ideal for you.
If you’re not that bothered about your car being off the road for a day or two, then the slower, more involved head gasket sealers might be a better choice.
Chemical Ingredients
Sodium silicate. Some love it, some hate it. It has a reputation for clogging up cooling systems, especially heating cores. That’s because it reacts with antifreeze and forms into a gooey mess. Some products include fibers that can also cause problems if they end up hardening in the wrong places.
If you see a product with sodium silicate in it, you’re best off draining and flushing the coolant, just to be on the safe side. There are, however, a number of products that contain sodium silicate that are actually safe to use with antifreeze, including  our top overall pick and its premium extra-strength counterpart.
Avoiding the Wrong Type of Sealant
If you search for head gasket sealers on Amazon, you’ll find many different products, a lot of which are not listed here. Why haven’t we included them? Well, many products are not suitable for head gaskets and are only good for specific types of gaskets, such as intake gaskets, or rubber seals.
You can easily spot these products as they often come in a tin and are referred to as “sealant.” You’ll also know whether they’re right or not by how they’re applied; if you need to pour it into the oil filler cap, or apply it with a brush, it’s not the right one.
The only head gasket sealers you should use will be put into the cooling system via the radiator or overflow tank.
If you’re changing a head gasket yourself, you’ll find that most head gaskets already have a protective material applied. Head gaskets are designed to be a specific thickness and they must be perfectly flat. Applying gasket sealant to a head gasket can alter the thickness, or make the surface uneven, which can result in misfires, compression issues, and other blown head gasket symptoms.
Stick to the products specifically designed for sealing head gasket leaks.

Pro Tip: Never add head gasket sealer to engine oil or fuel. Always put it into the cooling system. Be sure to check the manufacturer’s instructions for more details.

Blown Head Gasket Symptoms
What are the 3 key fluids engines need to run properly? If you answered fuel, oil, and coolant, you’d be correct. These fluids are usually kept separate from one another, although they can end up mixing together if something goes wrong with the head gasket.
Below are some of the main symptoms of a blown head gasket.
Overheating
Overheating is one of the most common symptoms people experience when their vehicle’s head gasket has blown. This is because the coolant is leaking into the combustion chamber, resulting in there not being enough coolant to keep the engine temperatures down.
It’s also one of the more serious symptoms, as the head can warp or crack, especially if the engine runs too hot for too long. This can damage additional parts of the engine too.
Loss of Power
A struggling engine that’s low on power can be a sign of a blown head gasket. You may also notice that your fuel consumption has increased significantly. This is due to the loss of compression within the cylinders, resulting in the wrong fuel to air ratio.
If your vehicle is wasting fuel due to a bad head gasket, you’ll literally be throwing money away!
Creamy Looking Oil
Oil is supposed to be a honey-like color and consistency, not creamy. If you take off the oil filler cap and notice creamy or milky looking oil, it’s not a good sign. It means that coolant has mixed with the oil, and that can often be caused by a blown head gasket.
It’s important to perform an oil and oil filter change if there’s coolant in the oil. Just be sure to only do it after the head gasket issue has been fixed, otherwise the fresh oil will become contaminated too.
Over Pressurized Cooling System
It’s normal for the cooling system to be pressurized when hot, but excessive pressure is not good. If the cooling system is over-pressurized, you may notice cracks in the radiator or the pipes.

Pro Tip: Never open the radiator cap while the engine is warm. There’s a good chance you’ll severely burn yourself – wait until the engine cools down before removing the cap.

Preventing Head Gasket Failure
Wouldn’t you agree that spending a few dollars and a little bit of time preventing the problem is better than spending thousands on fixing it?
As we’ve seen, one of the most common symptoms of head gasket failure is overheating. To avoid the engine from overheating, make sure the cooling system is in good condition. That includes the radiator, thermostat, coolant hoses, and the coolant itself.
Make sure the coolant level is topped up, and if it hasn’t been changed in a while, flush it out and refill with fresh coolant. Check there are no leaks in the piping. A good way to know if there are leaks is to check the coolant level every so often. If it goes down, there’s a leak somewhere.
As they say, prevention is better than cure, and that certainly applies here!
Head Gasket Replacement Costs
The average cost of replacing a head gasket runs into thousands of dollars, typically between $1,000 and $3,000, although it depends on several factors. That’s a huge cost when you compare it to the relatively cheap price of head gasket sealer.
Head gaskets themselves only cost a few hundred bucks at most, so why is the replacement so expensive? Well, unless you’re pretty handy with tools and know what you’re doing, you’ll have to pay a garage to replace the gasket. That’s where the big cost comes in: labor.
It can take anywhere from 5 hours to a couple of days to change an engine’s head gasket. It’s a pretty labor-intensive job, as many parts of the engine have to come off in order to get to the head. On top of that, everything has to be put back together again.
Is it worth replacing the head gasket? If the vehicle is relatively new, or low mileage, you may want to get it replaced. If you’re interested in doing it yourself, be sure to closely follow a guide so that you don’t cause even more problems. If it’s an older vehicle, or you’re strapped for cash, you may be better off with a head gasket sealer.
Remember: don’t ignore the symptoms of a blown head gasket. It’ll only get worse over time, and you may end up needing a replacement engine.
Frequently Asked Questions
Q: Do head gasket sealers really work?
A: Yes, head gasket sealers are an effective way of repairing a blown head gasket, assuming it isn’t severely damaged. For minor leaks, head gasket sealers can provide a permanent fix while saving you a lot of money.
Q: How long will the head gasket sealer last?
A: How long the sealer lasts depends on several factors, such as how bad the leak is and the product you use. For most small leaks, head gasket sealers can last a very long time – we’re talking years. For more severe issues, they may only be a temporary fix, lasting just a few months at most.
Q: What is the cheapest way to fix a head gasket?
A: The cheapest way to fix a head gasket by far is to use a good head gasket sealer. You’re looking at $100 or less, compared to thousands of dollars if you took your vehicle to a garage for a replacement head gasket.
Q: Are head gasket sealers just as good as a new head gasket?
A: In short, no. Nothing will be better than replacing the head gasket at a garage. Having said that, head gasket sealers can almost be as good at just a fraction of the price, so they’re certainly worth considering.
Wrapping Up
We understand how frustrating a blown head gasket can be, especially if you can’t survive without your vehicle. Trying to find the right solution without it costing the earth can be tricky.
Thankfully, there are plenty of solid products on the market designed to fix blown head gaskets quickly and easily. These head gasket sealers cost just a fraction of the price of having a new head gasket installed, making them a very appealing option.
Regardless of the route or product you decide on, remember to never ignore the symptoms of a blown head gasket. If left untreated, it can very quickly ruin the engine and the repair costs can spiral out of control. More

Talking about the cooling system is not nearly as exciting as talking about turbos or nitrous. Still, cooling is one of the most essential features of vehicle performance. After all, it doesn’t matter how much power an engine makes if it overheats and can’t actually put that power to the ground. If your motor starts getting hot, you can install oversized radiators or better fans. What if it’s your transmission that’s running too hot, though?
Simple: you install a radiator for your transmission.

A Quick Guide to Keeping Cool
Automatic transmission oil coolers, sometimes just called fluid coolers or transmission coolers, are relatively simple devices. After all, people had the whole heat dispersal thing figured out in the 1800s with in-home radiators. As fluid from your transmission gets pushed around, it flows through a metal pipe surrounded by fins. Those fins “radiate” the heat away from the liquid.
Being simple doesn’t mean there aren’t a lot of options on the market, though. Everybody thinks that they have the best design, and new innovations are happening every day. That’s where this guide comes in. We’ll give you all the tools you need to choose the best one for you, and give you our list of the top coolers on the market today. At the bottom of this guide, we get into the details and science with an in-depth guide.
First, though, there’s a question you really need to answer for yourself. Do you really need a transmission cooler?
Reasons to Get a Transmission Cooler
We’ll get into it more in our full guide, but unless you fall into one of the following categories, then the answer is, “probably not.”
You use your vehicle in ways it wasn’t meant to be used, like towing heavy loads or driving at high speeds on a track.
You live in an area where cars are more likely to overheat, like a winding mountain village or the middle of a desert.
You own a vehicle that has a factory defect causing the transmission to run hotter than it should.
You have a modified or custom car that does not have space for or never came with a factory transmission cooler.
You just really like the look of oil coolers and enjoy wrenching on engines.
Choosing The Right Transmission Cooler
Here are the general things you should look for when deciding which cooler is right for you.
Compatibility and Fitment
It’s the most obvious, but it is also a category that is easy to overlook. Some oil coolers are gigantic, and there won’t be room for them on your vehicle.
There are also a few different types of fittings going to and from your transmission. We’ll go over them in the “ >full guide, but basically, a push on fitting is more universal than an AN fitting. However, an AN fitting is more of a standard fitting in the performance world.
If you don’t know what kind you need, be prepared to buy adapters or do some DIY modifications.
The Style
In general, you probably won’t care if the cooler is a stacked plate or a tube and fin, since they all work. A plate cooler is technically more efficient than a tube cooler, but there are better ways to express that. If you really want to know, we’ll go through it more down in the full guide.
The more important thing to consider when looking at the cooler’s style is whether or not it includes a fan. A unit with its own fan can be mounted anywhere. A cooler without a fan has to be mounted in a place where it will receive a lot of airflow.
The Amount of Cooling Provided
Unfortunately, the actual amount of cooling a unit provides depends on many factors and is really hard to standardize. Sometimes manufacturers will express the cooling as a number, sometimes they will give you a general idea by using keywords like “heavy duty towing” or “racing,” and sometimes they will expect you to use the force to figure it out. As a very general rule, the bigger the radiator size, the more cooling it provides, and coolers with fans cool more than coolers without.
The only metric you will see used as a unit of measurement for oil coolers is the GVWR. That’s the number, in pounds, representing the maximum weight of your vehicle and what you can tow. Generally, a high number will require more cooling and more fluid.
Not all vehicle manufacturers adjust the GVWR in the same way, and not all oil cooler manufacturers use the same standards for measuring. Our advice is to not worry about numbers too much, and focus more on compatibility.
Here in the review section, we’ll cover various coolers and give a breakdown of what applications they are best suited for. Here are our picks for the top 10 transmission coolers on the market.

Top 10 Best Transmission Oil Coolers 2020
1. Best Cooler Overall: Derale Electra-Cool Remote Cooler

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Why we like it: It might be a little more expensive than others, but the Derale Electra-Cool is a high-performance cooler with an unrivaled application range.
Editor’s Rating:

Best Suited For
The Derale Electra-Cool is perfect for any vehicle owner that values performance. That included towing performance, drift circuit performance, or just dominating highway pulls down in Mexico.
It is fan-cooled and can be mounted anywhere. The fan cooling also keeps it compact enough that it’s easy to find a place to mount it. That makes it ideal for performance cars, newer compact trucks, and custom hotrods. It’s also perfect for old trucks that don’t have much room, or tiny cars that are being pushed too hard, or even motorcycles for your next “Long Way Around” tribute ride. Basically, anywhere you have fluids that need cooling.
Standout Features
The first prominent feature is the design. It’s compact, encased in an aluminum shroud, and includes a high flow fan. The whole package is easy to mount anywhere and will fit in perfectly no matter how crazy your build becomes.
Lending to that notion is the second big feature, the inclusion of AN fittings. It also includes barbed fittings for more universal fitment. If you really value performance, though, the -8AN fittings are how you’ll want to hook this cooler in.
How Does It Compare?
Let’s get the bad out of the way first. It’s a bit expensive, and the fan adds a layer of complexity that simpler units don’t have. If you really want a straightforward, radiator mounted cooler that works with almost any vehicle, the B&M SuperCooler on our list will probably suit you better. It’s cheaper and doesn’t have any moving parts.
If you are willing to tackle the added complexity, the performance to cost to size ratios of the Derale Electra-Cool is best in class.

Pros
It comes with factory AN fittings
It’s compact but still cools really well
The fan and size make it perfect for mounting anywhere

Cons
It’s more expensive than fanless units
It’s more complicated than other units and can be intimidating to install

2. Best Cooler Overall Runner-Up: B&M SuperCooler

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Why we like it: The B&M is a well designed, high-efficiency cooler that is rugged and super easy to install.
Editor’s Rating:

Best Suited For
The SuperCooler is really for anyone with a truck, SUV, or bigger vehicle who notices that the transmission is getting hot. It’s medium-sized, which is about the standard for most coolers, but it’s a very high-efficiency design. So even though it’s not very big, it still offers a great amount of cooling.
The big deal with the fitment is that the kit the SuperCooler comes in is really complete. You can use the threaded fittings it comes with or use the included barbed adapters. Unfortunately, it doesn’t have AN fittings, so you are better off with something else if you have a racecar.
It does come with bolts and brackets for mounting anywhere, meaning you can almost certainly find a place to install it. Just make sure it has good airflow because it doesn’t have a fan.
Standout Features
The one thing that really stands out about the B&M SuperCooler is the completeness of the package. It’s got threaded fittings with adapters, it’s got bracket mounts and funky zip tie mounts, and it even comes with tubing and hose clamps. It’s missing the bypass valve that the monster Tru-Cool kit we recommend has, but the B&M is half the price. It’s easy to buy a really nice bypass system for the money you’d save.
How Does It Compare?
The B&M cooler is one of the best value coolers you can get. It has tons of cooling potential, it has tons of installation options, and B&M makes a high-quality product.
There’s a lot of reasons that you might choose other products. If you need to install a cooler in a remote location, get the Derale Electra-Cool. If you need even more cooling, pay a lot more and get the Tru-Cool Max. If you want to spend a lot less, get the Hayden 678. If you want the balance between all those things in a simple to install, universal package? The B&M SuperCooler is the cooler for you.

Pros
It’s very versatile
High-quality
Really good cooling efficiency

Cons
It’s a little expensive for what it is
No AN fittings

3. Best Heavy Duty Cooler: Tru-Cool Max 40K

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Why we like it: If you are serious about towing, the Tru-Cool Max is rated for a gross vehicle weight of 40,000lbs.
Editor’s Rating:

Best Suited For
This is the mack daddy of cooling, and if you are about to pull a team of horses up to a secluded ranch in the high mountains, then the Tru-Cool Max 40k is for you. It takes up more room than anything else on our list, but the 40k in the name stands for a GVWR of 40,000 lbs. If you can tow that much weight, the size is not going to be an issue.
Standout Features
There are two really great features. First, and most importantly, it’s huge. It has a lot of surface area, it holds a lot of extra fluid, and it allows a ton of air to pull the heat away. That means you get as much cooling as is possible without spending even more and going to a fan cooled unit like the Derale Hyper-Cool.
Second, it’s super simple to install. Tru-Cool includes everything, even bolts. That’s unique for universal kits. Usually, companies make you source out everything. Tru-Cool seems to know that DIY types will love their products, so they go the extra mile. The brackets are pre-mounted to the cooler, it includes multiple different sized fittings and its own bypass.
How Does It Compare?
It’s hard not to say that the Tru-Cool cooler is a fantastic buy. It’s huge, so that eliminates it from many people’s lists, but it works great and is super easy to install. It is costly. However, you might actually save money over similar products because you’d have to buy the extras that the Tru-Cool includes separately.
The hardest part about an oil cooler this big is that if you already have a vehicle set up to tow, chances are it has a big transmission cooler from the factory. It’s a lot of money to spend on something that you may not need. If you are noticing some overheating while towing heavy loads, though, the Tru-Cool is the way to go.

Pros
It’s great for towing
It’s easy to install and includes almost any fitting you could need
The included bypass valve is a nice feature

Cons
Expensive
It’s too big for most vehicles, and vehicles big enough to utilize it might already have a good cooler

4. Best Premium Cooler: Derale Hyper-Cool Dual

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Why we like it: The Hyper Dual-Cool is ultra-compact but still has the cooling power of much larger units.
Editor’s Rating:

Best Suited For
The Hyper-Cool Dual is all about high-performance. It’s a bit complicated for just being a heavy towing cooler. The Tru-Cool cooler.
is just fine for large trucks, but if you are about to enter the King of Hammers competition, the Hyper-Cool is terrific.
It’s ultra-compact for the amount of cooling it produces. With two fans pushing air through the stacked plate system, you can get some of the best cooling on this list from a system that will fit anywhere and can be mounted anywhere. Dragsters, hardcore offroad buggies, and honestly just about any high-performance build where cooling is a very high priority can benefit from this Derale.
Standout Features
There’s a lot that stands out. First, it’s got two fans, so there’s a ton of cooling no matter where it’s placed. Second, it’s set up from the factory for custom and modified vehicles, with AN fittings and an aluminum shroud. Third, and perhaps most astonishingly, is the insane amount of cooling.
The Hyper-Cool Dual disperses more than 3 times the amount of heat as a really great tow cooler like the B&N SuperCooler. You read that correctly; the Hyper-Cool dwarfs most other coolers in terms of cooling performance.
How Does It Compare?
You’ll be paying a lot for that, though. It’s the most expensive thing on our list. If you don’t need that level of cooling, you’re spending a lot of money just to move air around. Also, like many high-performance parts, it’s just not noob friendly at all. If you are not comfortable doing a lot of wiring, you’ll be in for a bad time. Both the fans should be wired to separate controllers, and the whole thing should be wired into thermostat switches to keep everything optimal.
After you tackle the wiring, you need to plumb it in. Even though it comes with universal adapters, the only way to take advantage of the cooling is to have a robust system setup with bypasses. Trust us, if you are just getting into performance modifications, get the G-Plus cooler instead. When you outgrow it, come back for this Derale.

Pros
It has insane amounts of cooling performance
It’s ready from the factory to drop into high-performance vehicles
It can be mounted anywhere

Cons
It’s really expensive
You do need a high level of knowledge and skill to fully utilize it

5. Best Inexpensive Towing Cooler: Hayden Automotive 678

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Why we like it: The Hayden 678 is a great price and big enough to handle towing 5000lb trailers.
Editor’s Rating:

Best Suited For
The Hayden 678 is too big for small vehicles, but it’s got a ton of cooling potential. It’s got a GVWR of up to 24,000 pounds. For reference, that’s a motorhome towing a Jeep, or a 1-ton truck towing a few horses. That means for your average truck, this cooler is more than enough to keep your transmission from overheating.
Unlike really gigantic units like the Tru-Cool Max, the Hayden 678 is still a reasonable size and easy to shoehorn into older trucks that don’t have adequate factory cooling. For that reason, it’s easy to say that this Hayden cooler is the best general-purpose truck cooler on our list.
Standout Features
For a budget, fanless cooler, the efficiency is fantastic. To put it into context, it’s only a little bit bigger than one of our favorite coolers, the B&M SuperCooler. Despite that, it has very similar cooling properties.
How Does It Compare?
There are two main competitors on our list for the Hayden Automotive 678. The first one is one we mentioned above, the B&M SuperCooler. That doesn’t make for a very flattering comparison, though. They might have similar cooling capabilities, but the Hayden is lower quality, uses weaker metals, and is harder to mount. It’s a lot cheaper, but that’s about it.
For a much more flattering comparison, let’s contrast it with the other Hayden cooler on our list, the Transaver. The 678 is about ten dollars more, but for those extra dollars, you get a unit that is a lot easier to install and has a much higher cooling efficiency. If you tow a lot, the 678 is just a much better option, and you won’t regret paying for it.

Pros
It’s inexpensive
It’s easy to install
It’s great for towing

Cons
The quality could be better
It doesn’t have AN fittings

6. Best Budget Cooler: Hayden Transaver

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Why we like it: The Hayden Transaver is nothing fancy, but it will do the job.
Editor’s Rating:

Best Suited For
The Hayden Transaver is perfect for anyone that just needs a bit more cooling. It’s not going to stop you from overheating while towing a motorhome up a mountain. However, it will stop your truck from overheating as you pull a motorcycle trailer through the desert. This unit is just a perfect first step when you notice that you are running hot. It’s cheap enough that you can throw it on and see if it solves the problem before committing to a larger, more expensive unit.
They even made it moderately easy to mount. It’s medium-sized, so it will fit in almost anything as long as air can flow through it, and it includes its own tubing and push-on fittings. It’s a shame they didn’t attach any brackets for easier mounting, but the standard zip tie like things will suffice.
Standout Features
There really aren’t any; it’s about as straightforward as a cooler can be. It has a tube, some fins, and it comes with some tubing. That’s not a bad thing. It means nothing can break, but it can make it feel like other coolers are a much better value despite the low price.
How Does It Compare?
It’s a little unfair to compare this budget item to premium items like the B&M cooler. Yes, the Hayden Transaver is lower quality, is harder to install, and frankly looks uglier. It’s one-third the price, though, and that can forgive a lot of sins.
What is a fair comparison is to compare this Hayden to the other Hayden cooler on our list. They are about the same size, both use universal fittings, and both are under $50. This is where we have to be honest with you all and say that unless saving ten or so dollars is really important to you, you should get the Hayden 678 instead. The 678 is a lot more efficient. It’s about the same size, but it has more than twice the cooling power.
However, as we said before, the Hayden Transaver is a perfect first step. That’s where the price really matters. If you just are not sure if a cooler will solve the problem or are really worried about fitment, you can buy the Transaver and give the idea a good test.

Pros
It’s Inexpensive
It’s simple and durable
It will fit a really large variety of cars and trucks

Cons
It doesn’t cool very good for its size
The fit and finish leaves a bit to be desired

7. Best Small Car Transmission Cooler: VRacing 4 Row Universal

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Why we like it: At barely 5” tall by 14” long, the VRacing 4 Row is perfect if you just need a little more cooling for your commuter.
Editor’s Rating:

Best Suited For
If you need a cooler for towing a big trailer through the desert, this isn’t it. But if you have a small truck and just need a bit more cooling as you haul loads up long hills, this is perfect. The 4 Row is also perfect if you notice that your car is overheating on hot days. It doesn’t have a fan, so it needs to be mounted in front of your radiator, but it’s small enough that that isn’t an issue.
They claim it’s for performance cars too, but the reality is that most performance cars will be begging for the remote install capability that a unit with a fan will bring. Small trucks and cars that live in harsher climates or that are driven just a bit harder than they are meant for will really benefit from a small cooler like this, though.
Standout Features
It’s small and doesn’t cost much, but it doesn’t really stand out in any way. That’s not a bad thing. There’s nothing to go wrong with it, which can be just as valuable as any feature. There’s also nothing that makes it hard to work with. There’s no fan to figure out how to wire in and no AN fittings to adapt. It’s just, there’s also nothing that really makes it unique.
How Does It Compare?
It’s half the size of the Hayden Automotive 678 and less than half the cost. It’s also less than half the cooling power, so it all works out. If that’s all you need, then it’s perfect.
The simplicity of this cooler can lead to a few disadvantages. It has like, no install hardware. You basically just have to zip-tie it to a structural member. Second, the cooling efficiency isn’t high. On a small unit like this, efficiency is key to cooling performance, so that’s not great. It’s so cheap, though, it’s actually hard to criticize it too harshly.

Pros
It’s very inexpensive
It’s great for small vehicles where space is a concern
The simple design means there’s nothing that can break

Cons
You will have to find a DIY solution for mounting it
Not good for larger vehicles

8. Best Inexpensive Fan Cooled Cooler: G-Plus Racing Cooler

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Why we like it: The G-Plus cooler has a fan and costs less than half what a similar Derale unit costs. What’s not to love?
Editor’s Rating:

Best Suited For
Budget builders rejoice because the G-Plus is the perfect addition to any modified vehicle. It’s inexpensive enough to throw on an old K5 that needs to tow a travel trailer, and it’s approachable enough to stick on your old CRX before entering into the autocross.
The fan lets it work in any position, and it’s small enough to fit anywhere. The only issue that this G-Plus has is the opposite issue of the Mishimoto cooler on our list. For some reason, the G-Plus comes with AN fittings but no adapters. You’ll have to buy your own adapters if you want to make sure it fits your old work truck.
Standout Features
The price is the thing that makes the G-Plus standout. It is less than half the cost of the Derale electric cooler. You sacrifice quality for that price, and it shows in the finish of the unit. For instance, the seams aren’t sanded down, which is something you would never see on a higher quality cooler.
What you can do with a cheaper unit like this one is to test out the process before committing to a much more expensive setup. If you are on the fence about getting a cooler with a fan, then you can pick this up without feeling like you wasted a ton of money.
How Does It Compare?
As we said above, it’s the least expensive cooler with an electric fan on our list. We know that no one hates saving money, so we’ll count that as a good thing. It also comes in blue, if you want to add some color to your system.
It’s not all sunshine and rainbows, though. Like we said before, it’s just not as high quality as the more expensive counterparts. It won’t cool as well as the Mishimoto cooler, despite being a similar size, and the threaded inputs can be intimidating for first time DIYers. Oh, it’s also got terrible documentation. They even proudly proclaim that they don’t include instructions in the ad.

Pros
Inexpensive
Can be mounted anywhere
Perfect for learning about transmission coolers and your vehicle

Cons
The quality could be better
The lack of universal fittings in the kit is annoying

9. Best Racing Cooler: Mishimoto MMOC-F

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Why we like it: Mishimoto knows how to speak our language with words like “ideal for supercharged vehicles” and “lifetime warranty.” Wanna go fast? Mishimoto wants you to as well.
Editor’s Rating:

Best Suited For
At first glance, it doesn’t seem like the Mishimoto brings anything new to the table. It looks like the Derale Electra-Cool, and it costs about the same. It’s a lot smaller, though, which means you can stick it in tight engine bays while still getting excellent cooling from the attached electric fan. It’s perfect for old Jeeps where space is a huge issue under the hood, but where we think it shines is on track weapons.
Yes, we know that most track day people would turn up their noses at an automatic transmission. There’s a great oil cooler by Mishimoto here for those of you who live the three-pedal life. Not everyone does, though, and plenty of people enjoy driving modified automatics. Especially the quarter-mile junkies, and they need to keep those automatic transmissions cool if they want the best possible ET. Weight, space, and compatibility are all at a premium when building a vehicle like that. This Mishimoto fits the bill.
Standout Features
The 8” heavy-duty fan is the biggest thing that makes this Mishimoto awesome. That allows you to install it totally out of position if you need to, and keeps you cool while staging at the lights.
How Does It Compare?
It’s a lot more expensive than the G-Plus cooler on our list, so it’s got to be pretty good to be worth it. The good news is that it is worth the extra price if you need the most cooling possible out of a compact unit. It’s a very well built unit, and it comes with a lifetime warranty.
There is one big gripe we have with it, though. Usually, when you are building a high-performance car, you will almost always be switching to AN fittings at some point. Unfortunately, Mishimoto went for the more universal push fittings instead.
To give you an idea of how close a lot of these compact units compare, the inclusion of AN fittings is the only reason we like the Derale Electra-Cool better. The Mishimoto cooler is still absolutely fantastic.

Pros
The fan is really good
It’s easy to install because of the universal fittings
It’s very compact

Cons
It’s expensive for the size
We wish it had AN fittings and adapters instead of the straight universal connections

10. Best Tiny Cooler: Derale Compact Fluid Cooler

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Why we like it: It doesn’t make the best transmission cooler unless you have a very tiny transmission, but the versatility of the Derale Compact gives it a place on our list.
Editor’s Rating:

Best Suited For
It’s a little cooler for little things. It’s not even big enough to cool the transmission in your civic. You could stack a bunch of them together or something, but there are approximately 9 better ways on this list to cool a large transmission. Even if space is your biggest concern, a unit with a fan like the G-Plus cooler mounted in a remote location would be better than the relatively small surface area of this Derale.
Got a dirt bike, automatic scooter, or side-by-side, though? This little thing is perfect for keeping the transmission oil cool.
Standout Features
The size is really the most significant design element for this Derale. It comes stock with -6AN fittings, so you’ll have to convert it to barbed fittings to get a really universal fitment, but it’s small enough that it will fit on anything.
How Does It Compare?
When it comes down to it, the Derale Compact is just not big enough to be really useful for most transmissions, and that’s why we rated it so low. It’s really not a bad unit. Like most Derale products, it’s high quality and easy to mount. It’s perfect as a power steering cooler and perfect for cooling the oil on a motorcycle or other small engine. If you are looking for versatility, the size and AN fittings make it a great choice.
The problem is that they market it as an auxiliary transmission cooler, so we are reviewing it as such. It might lower your ATF temp a few degrees, but that’s nothing compared to the -20 you get from a small dedicated cooler like the VRacing 4 Row. The real kicker, though, is that the VRacing cooler is cheaper.

Pros
It’s tiny. Perfect for motorcycles and stuff
It has a high build quality
It comes stock with -6AN fittings

Cons
It’s kind of expensive for what it is
It’s tiny, and that means it’s not very good at cooling transmissions

Everything You Could Want To Know About Transmission Coolers
Up above, we promised you science, details, and tons of extra information. We like to keep our word, so let’s get into it. We’ll start with a deeper dive into the most important question.
Do You Really Need a Transmission Cooler?
If you go on to forums or follow truck builds on Instagram, you’re probably convinced that the minute you try to tow even the smallest trailer with your vehicle, it will instantly catch fire and explode. Unless, of course, you have a transmission cooler.
Here’s the big secret though: the people who design and manufacture trucks aren’t idiots. Most trucks, SUVs and even a lot of cars already have a transmission cooler integrated into the radiator. In fact, it’s usually better and more efficient than a lot of aftermarket ones. Unless you are actually noticing signs of your transmission overheating, then the answer is probably no.
There are a handful of good reasons to get an aftermarket cooler, though. Some don’t even require you to be having a problem first.
Your Transmission is Overheating
You can read about the signs here offsite, but the basic idea is that an overheating transmission will smell bad and behave strangely. There’s a few reasons a transmission can start overheating. There could simply be a design flaw for that make and model, or the owner could live in a really harsh and hot environment.
The first thing to check is the fluid quality. Bad or old fluid will cause overheating, so don’t jump straight into installing hundreds of dollars worth of upgrades when twenty dollars worth of ATF will do you just fine.
You Plan On Making the Transmission Do Extra Work
If you plan on really taxing the tranny, an oil cooler can save you from issues. Racing or towing heavy loads frequently can put a serious strain on a transmission and cause the temperatures to climb higher than the maker designed them for. Especially if you have a car or truck that doesn’t have a factory cooler.
You Are Messing With The Factory System Anyway
Modifying cars is a lot of fun. Any time you build power, you will probably also have to overhaul your cooling system. Most big aftermarket radiators won’t have an integrated transmission cooler, so you’ll need to buy a separate unit to ensure things stay under temp. What can be really handy about an aftermarket oil cooler is the ability to mount it anywhere. Depending on the extent of the modifications you are doing, you may be forced into buying an aftermarket cooler just because there isn’t room for the factory system anymore.

AN Fittings, Barbed Fittings, and Hose Clamps
After reading through our reviews, you might have some questions. Questions like, what is an AN fitting, and why do they keep talking about it? Why is an AN fitting better than a press on fitting, and why are all these press fittings different shapes?
Well, we’d like to answer those questions here.
AN Fittings
AN stands for Army Navy, because they were developed by the Army and the Navy. If you really want to know more, you can read the wiki about them here.
More importantly, AN fittings are standardized, threaded fittings for fluids used everywhere in the automotive world. They are measured by a dash number, and the higher the number, the bigger the fitting.
If you have ever gone to a place where there are a lot of high performance or custom cars, you’ve seen AN fittings everywhere, usually -8 and -10 fittings. Those are kind of your standard race car sizes. They are almost always either red or blue, and they are on the end of those cool braided hoses that run from reservoirs, to pumps, to filters, to coolers, and to the motor.
Push On or Barbed Fittings
Push on fittings have a ton of different designs, but they all function in the same way. You push a rubber hose over a tube that has ribs, barbs, or a bump to hold the rubber hose in place. Then you tighten a hose clamp around it.
They are dead simple and can be used with a lot of different types of hoses. You can even fudge the sizes. A hose barb that is too small for a hose can be made to work if you put enough force into the clamp, and a hose that is to small for the hose barb can be heated up and worked onto it anyway.
These types of connections are prone to wearing out and leaking, though. They can also be an absolute pain in the butt to work with after some time passes. Rubber hoses are especially prone to seizing in place. If a hose is older, you are much better off cutting it with a knife and replacing it rather than trying to carefully remove it and reuse it.
Threaded Fittings
Some of the coolers we recommend, like the B&M cooler, have threaded fittings that are not AN fittings. These threaded fittings are meant to be used with an adapter. You can either screw-in push on fittings or AN fittings. The advantages of having a threaded inlet and outlet are that you can choose what method you will use to hook up the oil lines, and they don’t have to be the same method for the in and the out. The downside is that you have to do some extra legwork to buy the adapter and install it.
The Three Main Types of Cooler
We touched on it briefly up above, but in addition to either having a fan or not, coolers come in three main types. The biggest differences between them are the efficiency of cooling and the price. The higher the efficiency, the more they cost. That usually means your budget will determine the type, so it’s not a very important thing to think about.
Tube and Fins– Cheap coolers like the Hayden Transaver are just a metal tube connected by metal fins. The heat gets absorbed from the tube by the fins and dispersed into the air. Simple, cheap, and good enough to cool things down a few degrees.
Plates and Fins- Plates are kinda like flat tubes. If you take a look at the Hayden 678 we recommend you’ll see that it has a ton of flat “plates” connected by a ton of tiny “fins.” The plates and fins design is higher efficiency because of the greater surface area, but the extra metal tends to make it cost more.
Stacked Plate- A stacked plate design is used in most premium coolers, like the B&M SuperCooler we recommend. At first glance, they look just like the plate and fin designs, but they are engineered to allow way better airflow and even more surface area. That engineering costs money, though.
A Transmission Cooler is Part of a System
The last thing we really want to touch on in this guide is to reinforce the fact that a transmission cooler is part of a system. It’s not enough to just buy a cooler and bolt it onto your truck; you also need to think about other vital components.
Thermostats and Bypasses
There is actually a sweet spot between too cold and too hot when it comes to most fluids. Your engine’s cooling system has a thermostat that only opens when the motor is warmed up. When you install a transmission cooler, you want it to behave in the same manner.
You do that by creating a bypass loop so that the transmission fluid can flow through the stock internals and warm up without having to flow through the aftermarket cooler. There are electric thermostats that hook up to bypasses controlled by an electric signal, and bypasses that work like a radiator thermostat. You will want to research since builds are more dependent on the individual vehicle than anything else.
Space Conflicts
Not only are there components that make up the transmission cooling system, but the transmission itself is part of a larger system that makes up your power train. That means you have to be careful to install coolers and hoses in a place where they will not interfere with other components. A fancy new cooler won’t do you any good if the radiator fan cuts the hose in half.
Relays and Wiring
Coolers with a fan have an extra step when installing them, and that extra step is wiring in the fan. Generally, you don’t want the fan to run all the time, and that’s for the same reason you would install a bypass. When the engine is cold, you are just wasting energy by letting the fan run constantly. The easiest thing to do is get a thermal switch, like this one, and wire the fan into it.
Otherwise, wire into a relay that’s triggered off the main thermostat or the computer. If you are hardcore, wire it to a switch on your dash and just turn it on when you need it.
Keep it Cool
The number one killer of performance transmissions is heat. There’s no reason not to solve that issue. Coolers range from cheap to still less than a good intake, and it’s a small price to pay compared to the thousands of dollars it would take to replace a transmission that you know is running hot. Don’t wait; grab some zip ties and some ATF and order one. More