How To Know If Your Head Gasket is Blown-Step by Step

This article is a complete step by step guide for beginners to diagnose a blown head gasket on any car in minutes.

How To Know If Your Head Gasket is Blown

  • Car overheating on the temperature gauge
  • Interior heaters go cold and won’t heat up
  • White or Blue Smoke coming from the exhaust
  • Water coming from the exhaust
  • Water bubbling out of the radiator or coolant tank
  • Oil in the water reservoir
  • White creamy gunk inside the valve cover and engine oil cap
  • Creamy milky looking oil on the dipstick
  • Loss of Power
  • Misfire in the engine

How To Diagnose a Blown Head Gasket

If your head gasket is blown it is pretty easy to diagnose if you know what to look for. The most common symptom of a blown head gasket is the engine will start to overheat, this can start out occasionally but it will eventually happen every time you run the engine.

cylinder head

Another common symptom of a blown head gasket you will notice is excess white or blue smoke coming from the exhaust. This is because water or oil is leaking into the combustion chamber causing excessive smoke.

This is why you might have noticed the car being low on coolant. If the gasket is really bad you will see water coming from the exhaust although this is usually only in extreme cases.

If this sounds like your car, the next step is to open the hood and remove the engine oil cap. If you turn it over and look at the inside of the cap, this should be clean. If the cap is covered in creamy-looking gunky stuff, like below, this is a good indication along with the other symptoms that the head gasket is blown. The gunky stuff is a mixture of oil and water.

blown head gasket symptom

One last DIY test you could do is by safely removing the radiator or coolant tank cap. Make sure the engine is cooled down before removing the cap because if the cooling system is pressurized hot water will fly from the radiator cap.

Once the cap is off, start the engine. If the water in the radiator is bubbling or surging out of the radiator it means the head gasket has blown and will need to be replaced.

What is a Head Gasket?

The Head Gasket is the most vital gasket in the engine. This gasket seals the combustion chambers, making it possible for compression to build up in the chamber.

head gasket

Without compression, the engine would not start or run. The head gasket also seals the oil into the oil galleries and coolant into the coolant passages keeping them separate from each other along with stopping them from getting into the combustion chamber.

What is a Blown Head Gasket?

This is when the head gasket melts or gets a hole blown in the gasket. Once the gasket is damaged it will no longer seal correctly, meaning it will either leak combustion gasses from the compression chambers or it will leak oil into the water or compression chambers

blown head gasket

The cause for a blown head gasket is due to overheating of the engine. This is usually caused by low levels of coolant, the cooling fan not working correctly, or a clogged radiator.

If the head gasket blows the car will begin to overheat and eventually lose compression. Without compression, the car will not start or run.

Can you Drive a Car with A Blown Head Gasket?

Yes, you could drive the car for a short period of time but you will continue to do more damage to other components the longer you drive it if your car is overheating.

When the head gasket is blown it no longer holds coolant in the engine therefore the engine will get extremely hot. This extreme heat will eventually warp and crack the cylinder head or completely seize the engine if it gets hot enough.

Is There a Quick Fix for a Head Gasket?

No there is no quick fix for a blown head gasket. However, there are some excellent sealers on the market that will temporarily seal your head gasket until you can get the gasket replaced. Do not mistake this for a fix. The companies say the head gasket sealer is permanent but it NEVER is.

Where is The Head Gasket Located?

The head gasket on a car is located between the cylinder head and the engine block.

Photo by: Car Throttle

Can you Fix a Head Gasket Yourself?

Yes, you can replace a head gasket yourself if you have experience working on engines. If you are not experienced I would not recommend doing this job yourself. If a head gasket is done incorrectly for any reason it will not seal and you will have to remove the cylinder head again to fix it.

Although If you do decide to replace the gasket take a look at this article to find the best head gasket kits on the market.

Best Head Gasket Sealer for Honda

  • K Seal
  • Blue Devil Gasket Sealer
  • Steel Seal Gasket Sealer

K-Seal Pour and Go Head Gasket and Block Repair

Photo by: Amazon

K seal is definitely the best out there when it comes to engine and gasket sealers. This sealer can fix blown head gaskets, and cracked heads, and blocks. This is the sealer I use if I really need to get by for a few days but there is no substitute for a new gasket.

The good thing about this sealer is there is no need to flush or drain out the coolant system for the sealer to work.

K Seal claims this is a permanent fix. Maybe they’re right. BUT I would doubt it, although I couldn’t say for certain because I always replaced the gasket after a few days. You can get a bottle on Amazon for $20.86 which isn’t bad if it means prolonging the agony of paying around $1000 for a new head gasket if you’re paying a mechanic.

BlueDevil Head Gasket Sealer and Radiator Flush

Photo by: Amazon

Blue Devil is equally as good as K Seal when it comes to sealing your engine. The good thing about this is that it comes with a radiator flush which could well be the reason your head gasket is blown in the first place.

Cheaper engine sealers clog internal passages inside your engine and cause more problems than they fix but Blue Devil has been tested and proved this doesn’t happen.

Steel Seal Head Gasket Sealer

head gasket sealer
Photo by: Amazon

Steel seal is well known for its sealing performance although there have been some cases of this not reaching the cracked or blown gasket. However, Steel Seal does promise a 100% money-back guarantee if the problem isn’t fixed which is reassuring.


With over twenty years worth of experience in the motorsport industry and many happy customers you can rest assured that the information you get here on is 100% free, reliable and without the fluff.

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