Best Head-Gasket Sealers: Permanently Solve Coolant and Engine Oil Leak Problems

Permanently seal cracks and coolant leaks with our top picks for head-gasket sealer.

byNoelle Talmon|
Best Head Gasket Sealers
Share

We may earn revenue from the products available on this page and participate in affiliate programs. Learn more ›

Faulty head gaskets are no fun to deal with. This type of malfunction can cause a lot of issues, including engine misfires and oil leaks. While a bad head gaskets will eventually need to be replaced in most cases, gasket sealers just might buy you some time to get you by until you can afford to do so. There are numerous head gasket sealers available online and in stores, some intended to be used as mentioned, others to promote a seal during installation. This guide will help you decide which is best for your situation.

Best Overall

Steel Seal Blown Head Gasket Fix Repair Sealer  

Summary
An easy-to-use product that works well with both diesel and petrol engines. It’s a multi-use sealant that solves problems associated with head gasket leaks, heater core, and freeze plugs.
Pros
  • Easy to work with
  • Helps eliminate overheating problems
  • Improves vehicle mileage
  • Reduces smoke emissions and oil consumption
  • Works well for old trucks that cannot hold water
  • Backed by a 100 percent money-back guarantee
Cons
  • Expensive
  • Will only work well if you flush the engine first
Best Value

K-Seal ST3501 HD

Summary
An affordable sealant known to solve common problems fast and blends easily with antifreeze. Can eradicate tapping or flushing and repair other problems such as freeze plugs, heater cores, warped gaskets, and cracked heads.
Pros
  • Permanent solution to coolant leak repairs
  • Mixes well with all antifreeze
  • Doesn’t require engine flushing or draining
  • Fixes multiple problems
  • Affordable
Cons
  • Sealant might not work well if the head gasket has extensive damage
  • Discolors some brands of antifreeze
Honorable Mention

BlueDevil Head Gasket Sealer

Summary
A head gasket sealer that is compliant with ASTM standards and permanently seals the blown head gasket on all types of engines. The sealer is safe and easy to use.
Pros
  • Sealant is a permanent solution that works well during any weather condition
  • Prevents coolant leaks
  • Prevents the loss of radiator fluids
  • Helps with resolving cold start rough idle
  • Manufactured by a reputable company
Cons
  • You may have problems with the thermostat after using the product
  • May block the cylinder tubes and passages

Summary List

Our Methodology

We selected this sturdy, extensive selection of head gasket sealers based on user experiences, effectiveness, price, and value. Some are on the higher-dollar side, some are very inexpensive. There are many sealers out there that have questionable effectiveness, but these three products' reviews indicate that all hope is not lost. While a liquid sealer isn't the most optimal fix for a head gasket, it could be enough to stave off a lofty repair bill for a good, long while. But of course, your mileage may vary. For more on how we select products for our reviews, check this out.

Best Head Gasket Sealers: Reviews & Recommendations

Best Overall: Steel Seal Blown Head Gasket Fix Repair Sealer

Pros

Seals fast

Designed to work in older engines

Works in gasoline and diesel engines

Cons

Only works when a flush is performed prior to use

Expensive

The Steel Seal gasket sealer comes in two bottles that are enough for people with bigger engines, such as eight-cylinder engines. The product comes with easy-to-follow instructions, though you need slight automotive knowledge to use it. This sealer is designed to solve different blown head gasket symptoms, which include white smoke, engine overheating, external leaks, and watery oil.

The biggest potential drawback is the need to flush the system prior to its use. That, stacked with the high cost, will push many to consider other options.

Best Value: K-Seal ST3501 HD Multi Purpose One Step Permanent Coolant Leak Repair

Pros

Inexpensive

Does not require an engine flush prior to use

Treats other coolant leaks

Cons

Reported coolant discoloration post-use

Users report effectiveness in small leaks only

The K-Seal Coolant Leak Repair is a “shake, pour, and go” head gasket sealer that comes with an affordable price tag. This product’s standout feature is the fact that it’s compatible with any antifreeze product, which eliminates the need to flush out the coolant system before application. It’s a multipurpose product, and you can safely use the sealant to solve other leakage issues related to the heater core, engine block, water pump casing, and freeze plugs.

Unfortunately, there are some issues with this product. It is an affordable product that's easy to use, but it really is suited for only small leaks. Reports of coolant discolorations may indicate the need to replace coolant once it's done its job.

Honorable Mention: BlueDevil 38386 Head Gasket Sealer

Pros

Works on cracked, leaking, and warped heads

Works with any cylinder count

Can simply dump into the engine

Inexpensive price

Cons

May cause blockages in the engine

Works most effectively with fresh coolant

The BlueDevil gasket sealer is an easy-to-use sealer that saves you money in repair bills for your car. It’s a professional-grade head gasket sealer that also solves leakage issues associated with the heater cores, freeze plugs, and other components associated with the coolant apart from the radiator core. As long as you follow the instructions provided, the sealer provides a permanent leakage repair solution.

It works so well, in fact, that it can even cause blockages if it's not used correctly. It also works best when fresh coolant is added to the system, meaning you may want to flush the engine before and after using it to avoid issues.

Our Verdict on the Best Head Gasket Sealers

The Steel Seal Blown Head Gasket Fix Repair Sealer is our top pick for the best overall permanent head gasket sealer. It works well on older and new vehicles and is suitable for cars, vans, SUVs, and trucks. If your budget is a little tight and you still need a professional-grade sealer, check out the K-Seal ST5516 HD. It’s an affordable sealant that comes with most of the qualities you can find in more expensive brands.

How Much Are Head Gasket Sealers?

$20 includes head gasket sealers that come in small containers weighing under 16 ounces. The content of these containers can help you handle leakages associated with the head gasket effectively, though you might have to get a bigger container for larger engines. If you are looking for a larger container that can fix a couple of leaks, then look into products in the $25-$50 price range. The containers typically have 32 ounces of fluid. That’s enough to handle six- and eight-cylinder engines.

FAQs

You've got questions. The Drive has answers.

Q. Are head gasket sealers safe for the engine?

A. Good-quality head gasket sealers are designed to work effectively without compromising the engine's function. Most sealants have been tested and known to work well with either diesel or petrol engines and with different materials such as plastic, aluminum, and cast iron.

Q. Are head gasket sealers better than complete gasket replacement?

A. This depends on the level of damage you are dealing with. Most head gasket sealers provide a permanent solution to minor leakages. They will, however, only offer a temporary solution to severe leaks, and eventually, you might need a complete gasket replacement.

Q. How long will the head gasket sealer last after application?

A. Different brands have different qualities and while some will last long, others will not. It also depends on the severity of the damage to your head gasket. Most sealants offer permanent solutions to minor leaks but can only last for a maximum of six months if the damage is severe.

Q. Will the sealant clog other holes in the system?

A. Sealants are designed to fill up small holes in the head gasket. Most, however, can also clog up leaks in the transmission, power steering, and hydraulic systems. If you are dealing with bigger holes that the sealer cannot handle, you should think about replacing the head gasket. 

Why Trust Us

Our reviews are driven by a combination of hands-on testing, expert input, “wisdom of the crowd” assessments from actual buyers, and our own expertise. We always aim to offer genuine, accurate guides to help you find the best picks.

Learn more
stripe
Car PartsEngine & Motors