The Causes of Head Gasket Failure and How to Prevent Gasket Leaks

The head gasket is perhaps the most important gasket in a modern car’s engine. The head gasket is typically installed between the engine block and the cylinder head of the motor. The job of the head gasket is to form a tight seal between the combustion chambers and the oil and coolant passages in the engine.

When it fails, coolant will enter the combustion chamber and eventually mix in the engine oil. Since the coolant is NOT designed to lubricate the engine, gasket leaks will lead to serious and expensive engine damage.

In this article, we will discuss the causes of head gasket failure and how to prevent gasket leaks from occurring.

Symptoms of Head Gasket Failure

The symptoms of gasket failure can vary considerably depending on how the head gasket failed. Remember that it can fail in many different ways and the symptoms will depend on which area of the gasket was damaged or broken in the first place.

  1. Coolant in the engine oil. Pop open the hood and pull out the engine dipstick. If the oil is ‘yellowed’ or has the color and consistency of mayonnaise, you are looking at the symptom of head gasket failure. In order to confirm your suspicion, loosen and remove the oil cap on top of the engine and check under the cap. If you see yellowish gunk on the cap, this means the coolant and water mixture has already mixed with the engine oil. If this is the case, get your car checked immediately.
  2. Engine misfiring. Misfiring can be caused by a lot of reasons like bad or fouled up spark plugs, ignition coil failure, or even a dirty fuel filter. However, in the presence of yellowish engine oil and engine misfiring, you are most likely looking at gasket failure.
  3. White smoke from the exhaust. If you happen to be one of the owners of a 2016 to 2017 Ford Focus RS, you probably heard of the head gasket issues that are currently much talked about in various Ford forums worldwide. According to Road & Track magazine, the issue will manifest itself via the presence of persistent white smoke on the exhaust, particularly when you rev the engine to higher RPMs. This problem is caused by an incorrectly delivered head gasket.
  4. Engine overheating or unusually high engine temperatures. Since coolant and water is leaking to the combustion chamber (and eventually burned along with the air and fuel mixture), this also means the motor will be low on coolant, which will inevitably cause engine overheating issues. You might also notice some steam exiting the exhaust. In this case, the engine temperature gauge will display a higher-than-normal temperature reading.

Causes of Head Gasket Failure

  1. Engine design. Similar to the gasket issues of the Ford Focus RS mentioned above, the design of the engine might have something to do with repeated head gasket failures. Some vehicles have more problems than other makes and brands and this is due to engine design.
  2. Cracked cylinder heads. In most cases, the head gasket is not the primary cause of the problem. If your engine has a cracked cylinder head, it will be unable to form a tight seal between the engine block. Take note that even the smallest of cracks in the cylinder head is enough to cause failure of the gasket.
  3. Corrosion in cylinder head surface. Minor imperfections in the cylinder head surface like corrosion, scratches, and indentations might cause the gasket to fail prematurely. Corrosion in the cylinder head surface is caused by improper servicing of the cooling system. This is bad news since extreme corrosion means you will need a brand new cylinder head. If the problem is less serious, a professional machine shop can restore the surface to make it smooth again.
  4. Warped cylinder heads. This problem is most evident in vehicles equipped with aluminum cylinder heads. If the surface of the cylinder head is warped, it will be unable to form a tight seal with the engine block and will not hold the head gasket properly. Warped cylinder heads are caused by repeated engine overheating.
  5. Pre-ignition and engine detonation. Engine detonation and pre-ignition will cause the engine pressure and temperature to rise prematurely. This is caused by burned exhaust valves, overheating spark plug tips and carbon deposits in the combustion chamber. The elevated pressure and temperature inside the cylinder head will cause a lot of stress on the head gasket, which will eventually lead to engine failure.

How to Prevent Head Gasket Failure and Gasket Leaks

Luckily for you, there are a lot of things you can do to prevent failure and leaks of gasket.

  • Replace the engine coolant according to the recommendations of the manufacturer. Some cars will need fresh coolant every 60,000 or so miles, while others will need coolant replaced every 120,000 miles. The trick is to determine the pH level of the coolant. If the coolant has a pH reading below 7.0, it is time to flush and replace the coolant.
  • Only use distilled water when topping up the radiator. Tap water contains hard minerals and deposits that can cause corrosion on the surface of the cylinder head. Only use distilled water if you need to add water to the cooling system.
  • If you are installing a new head gasket in your car, make sure the head bolts are torqued to the proper specifications. This is perhaps the most important step you can take to eliminate repeated failure of the head gasket. Make sure you are using a high-quality torque wrench that can provide the proper torque readings when tightening the gasket bolts. Make sure to inspect the threads of the head bolts before installing. Damaged or dirty threads will not only give false torque readings, but it will decrease the clamping force of the bolts by up to 50%.
  • Finally, if you notice your car has idling or performance issues, have it checked immediately. Prolonged engine problems will cause unnecessary stress on engine components and the head gasket itself.


The head gasket is an important part of maintaining a smooth and reliable engine performance. If you notice any of the symptoms of head gasket failure, it will be best to have it checked immediately to prevent extensive engine damage.

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