5 Causes for a Blown Head Gasket

A head gasket removed from a vehicle.

A blown head gasket can be very bad news. It’s either going to cost you money to have it fixed, or you’re going to have to do the job yourself. Either method will cost money, but doing it yourself can save you the cost of labor. Before you can repair it, however, you need to know the cause. This can be a problem since there can be a number of causes for a blown head gasket.

1. Overheating

The biggest cause of a blown head gasket is overheating. Usually, the head gasket armor around the cylinders can become crushed, and if this happens, the seal is lost and your engine will lose compression, leak coolant, and the gasket will erode.

Before replacing the gasket, it’s vital that you find the cause of the overheating. It could be due to coolant leaks in the engine, the hoses, the radiator, or the water pump. These have to be found and repaired. It could also be due to the cooling fan not working or the radiator being clogged. Again, these need to be fixed or, in all likelihood, you’ll end up with another blown head gasket again shortly after your repair.

2. Installation Error

If you’ve had a blown head gasket replaced on your car and solved the problem of why it blew in the first place, the likely cause this time will be installation error. This is not particularly uncommon.

The head bolts need to be tightened in the correct sequence and set to the proper torque. They also need to have clean threads that aren’t stretched or damage. The cylinder head surfaces and engine block also need to be smooth, clean, and flat.

Any one of these factors, or a combination of them, can cause a blown head gasket. Remember, too, that sealer should only be used on non-coated, one-piece steel head gaskets. However, establishing this as the cause can be difficult. You’ll need to eliminate other possibilities first.

3. Hot Spots

There are engines that are prone to hot spots between the center cylinders in the cylinder head, although aftermarket head gaskets for these engines are reinforced to lessen the possibility of a blown head gasket.

However, if you have an older car, the hot spot could be the cause especially if your old head gasket has been replaced by one that’s not reinforced.

4. Pre-ignition Problems

Pre-ignition problems can cause this problem as well, especially if you only use your car for city driving. With pre-ignition, there’s a hot spot in the chamber which causes ignition of the fuel before the spark plug has a chance to fire. It could also be due to detonation. This happens if the spark timing is too advanced or the fuel mixture isn’t rich enough. It causes carbon deposits to build up and ultimately erodes and blows the part.

5. Bad Head Gasket

In some cases, the original head gasket for the car can just be very badly designed and the poor design can cause a blown head gasket over a period of time. A little research will establish if your vehicle is prone to poor designs. Once you replace it with a good head gasket, you should not experience any further failures.