Head Gasket

Head Gasket

A head gasket performs the function of a sealer between the engine head and the engine block. Its damage will cause an array of problems, including the following:

Engine overheating 

A head gasket keeps coolant from reaching the combustion chamber. If it breaks, the coolant may find its way to the cylinders, interrupting normal coolant circulation that is crucial for efficient engine cooling.

Low coolant level

A broken head gasket will cause internal or external leaks. Whichever happens, the coolant level will reduce.

Your heater blows cool air

Your hot coolant is what warms up the air that passes through the heater. The lack of hot coolant due to your leaking head gasket will cause the heater to malfunction.


A faulty head gasket can either cause a coolant leak or reduce lower engine compression. In either case, this will result in incomplete combustion and, therefore, engine misfires. 

White smoke from the exhaust

If your coolant reaches the combustion chamber due to the damaged head gasket, you’ll see white smoke with a sweet odor coming from your exhaust.

Your dashboard’s check engine light comes on

Once the engine control unit detects an engine misfire caused by a leaking head gasket, it will notify you of the problem by tuning on the check engine light.

Your engine oil foams up or coolant has got a brown tint

There are a lot of oil and coolant passages in the cylinder block. If your head gasket fails, oil and coolant can mix together, making your oil foam up or coloring your coolant in brown.

Engine damage

Your engine is not designed to compress fluids, so if the coolant enters the cylinders, this may cause catastrophic damage to the engine. Besides, the mix of oil and coolant is not able to provide efficient engine lubrication.

What is a head gasket?

A head gasket provides a tight seal between the engine head and the cylinder block. Its failure may become a source of numerous engine problems, such as poor engine compression, overheating, internal and external coolant leaks, etc.

A head gasket is subjected to a lot of abuse during engine operation. It has to withstand extreme temperatures and high combustion pressures. Moreover, due to the specifics of engine operation, it must compress and recover very fast, while maintaining a seal.

While a head gasket is usually an inexpensive part, problems that it causes may cost you a pretty penny. Let’s check the most common reasons for its failure:

Engine overheating

Abnormal or incomplete combustion along with engine overheating are the most common causes of a failed head gasket.


A head gasket may wear out over time. Besides, some older vehicles came with a head gasket made of less durable materials.

Manufacturing defect

Your head gasket may also get failed because of a manufacturing defect or the engine flawed from the factory.

Improper installation

Incorrect head gasket installation or removing of the cylinder head may cause damage to the gasket.

Will it cost me a bomb to fix the problem?

While a head gasket itself is easy on the pocket, its replacement may cost you a pretty penny. That’s why it is very important not only to fix the problem, but also to find out what was its cause. 

If your head gasket fails due to an engine problem, the latter must be addressed first. In some cases, both engine block and cylinder head must be machined for their proper installation.

The lion share of the repair cost is the labor involved. It is reasonable because a mechanic will need to take apart and reassemble the top of the engine, which usually takes a couple of days or even longer if it is a quite big engine. 

Depending on the complexity of the problem and damage caused to the engine, you may need to purchase new spark plugs, coolant and other engine related parts. This will also affect the cost.

The worst scenario is replacing your engine with a new or remanufactured one, which is the most expensive option. That’s why if you drive a very old car, you may consider purchasing a new vehicle.