Blown Head Gasket

How to Check if Your Head Gasket is Blown

In Engine by 1 Comment

Most cars require three different fluids to run – air-fuel mixture, engine oil, and coolant.

None of these fluids should be exposed to each other. The head gasket is a device that ensures that this does not happen. The head gasket is placed between the cylinder head and the engine block.

The thickness and size depend on the vehicle type and manufacturer. The head gasket seals the combustion chamber and prevents the exhaust gases from flowing back. It also keeps engine oil and coolant away from the combustion chamber.

A blown cylinder head gasket can cause further engine problems. Various tests are carried out on the cylinder head gasket to uncover the cause of a blown cylinder head gasket.

What causes a head gasket to blow?

The gasket is well hidden between the engine block and cylinder, making it difficult to diagnose a blown gasket. The gasket prevents interaction between the combustion gases and the coolant, which can sometimes operate at different temperatures. After frequent use, the gasket can develop leaks and, if not repaired, explode. Oil enters the engine through the drain valve.

When the cylinder head gasket explodes, the car starts to use a lot of oil. You may also want to check your pistons before you conclude that the gasket is the cause. A whitish smoke emitted by the car is the first sign of a blown cylinder head gasket.

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Also the ability of a car to stay in neutral decreases. A blown cylinder head gasket should be repaired immediately as oil is needed to lubricate the engine. Without lubrication, the bearing will wear and there will be a loss of viscosity.

The cost of driving with a blown cylinder head gasket is so high that it is not recommended to try it. You will find that the problem is serious if you are constantly forced to refill the radiator after a few miles of driving.

How to identify a blown gasket

White Smoke From Exhaust

There are several ways to check if your head gasket is blown. Here are some of the most common signs.

White smoke coming from the exhaust

As the gasket prevents the coolant from hitting the combustion gases at all times, if it leaks, the coolant escapes through the exhaust pipe. This shows up as white smoke with a sweet smell. The white smoke is still present even when the engine has warmed up. Depending on the leakage, the white smoke can be large or small in quantity. Further tests of the cylinder head gasket are necessary to ensure that the gasket has blown.

Bubbles in the radiator

Another sign of a leaking head gasket is when you notice bubbles in the radiator. The gasket prevents the coolant from being affected by the exhaust gases. If this happens, you will notice bubbles in the radiator, even when it is cold. If you have a chemical tester, you can check the chemical composition of these gases.

Milky oil

A faulty head gasket causes the coolant to flow into the combustion chamber, through the piston rings, and into your engine oil. Since oil and water do not mix, a milky substance is created. You can check this leakage by examining the end of the dipstick. Dirty oil means that your engine is not working efficiently. It could lead to further damage to the cylinder walls and camshaft bearings. It could also cause corrosion of metallic engine parts.

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Overheating engine

If you travel long distances and have a blown cylinder head gasket, you will notice that the engine overheats. The cause of overheating is the lack of a coolant to cool the engine and the penetration of coolant into the combustion chamber, which hinders the complete combustion of the gases. If the problem remains without immediate attention, the metal parts in the engine will expand and form cracks. This will result in permanent damage to the engine and you will be forced to buy a new engine.

Dirty spark plugs

This is not a final head gasket test, but when the coolant enters the combustion chamber it leaves white deposits on the spark plugs. However, there are other causes for this and you must confirm this with other tests.

How to test for blown head gasket

One of the most important head gasket tests you can do is to check for traces of carbon dioxide in the radiator. Since the head gasket prevents the mixing of combustion gases and coolant, you will find some of the combustion gases in the coolant if the gasket is broken.

A tester is used that changes color when exposed to carbon dioxide. When you perform the test, first warm up the engine and then lower the coolant in the radiator to allow enough space for the test. Test the vapors that escape through the coolant. For most testers, you should wait for yellow color.

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Further head gasket testing is required to confirm the results.

You can also try driving a few miles with a loose radiator cap. If you find that the engine has used up most of the coolant during a 50-mile drive, the gasket could be leaking. For this head gasket test, drive the car at 50mph.

How to prevent further blown head gasket problems

If you have replaced your head gasket, you must find solutions to the problem to prevent the problem from reoccurring. Make sure that the coolant is always filled when its pH drops below 7.0. If you notice that the engine overheats while driving, stop at the side of the road and turn off the engine.

It is also advisable that you obtain your cylinder head gasket from reputable manufacturers. Most gaskets on the market are of inferior quality, which leads to the premature failure of the head gasket.


A blown cylinder head gasket, if not repaired, can cause further engine problems. The first signs of a blown cylinder head gasket are white smoke coming out of the exhaust pipe. You can do a carbon dioxide test in the radiator – traces of the gas are a sign of a blown cylinder head gasket. It is not recommended to drive around with a blown cylinder head gasket. If you encounter the problem, stop the engine immediately and perform the head gasket tests mentioned above.

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1 thought on “ How to Check if Your Head Gasket is Blown ”

  1. Hi magnus i have a Jetta make 2 cli 1989 fuel injection my car doesn’t idles free first it idle at 10 bars but now when it gets hot after idling a few seconds it starts to go up and down what can it be

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