What Causes a Blown Head Gasket?

An engine's head gasket.

You’ve probably heard it can be an expensive repair, but do you know what causes a blown head gasket? Here’s what your head gasket does to keep your engine running smoothly, common causes of a faulty one and what you should do if you suspect something is wrong.

What Is a Head Gasket?

A head gasket is a relatively straightforward part. It’s basically a seal that sits sandwiched between the engine block and the cylinder head. The head gasket doesn’t look like much, but it’s one of your engine’s essential components.

The head gasket does two things. First, it creates a seal to keep the internal combustion process contained. Second, it keeps coolant and oil from mixing as they circulate through your engine near each other.

Getting to a head gasket can be tricky and that’s what makes this a difficult repair. Replacing it means removing the engine’s head, which is a challenging job that’s not for everyone.

What Causes a Blown Head Gasket?

There are several possible causes, including engine age, but two common culprits are overheating and preignition issues.

1. Overheating: When an engine overheats, the metal expands and pinches the head gasket so it no longer seals properly. A telltale sign of this problem is white smoke coming from your exhaust, which is from coolant leaking around the head gasket.

2. Pre-Ignition Problems: If the timing of the combustion process is off even slightly, it can send too much pressure into the cylinder head. This can cause the head gasket to fail. If this happens, you may notice the car running roughly, especially when you first start the engine or at idle.

Preventing a Blown Head Gasket

The best way to prevent a blown head gasket is to ensure your coolant system is functioning properly. Start by checking the radiator and the coolant overflow tanks whenever you check the oil. While you’re under the hood, inspect the radiator hoses, too. If there are splits, frays or any signs of damage, get them replaced promptly.

Also, take note of any leaks under your car. If you see a puddle of coolant or if you find yourself refilling the coolant frequently, those are signs of an issue with your coolant system that need to be addressed.

What Should You Do if You Suspect a Blown Head Gasket?

If you think you have a blown head gasket, you should get it repaired as quickly as possible. A blown head gasket left alone can cause additional engine damage that will only add to your repair costs. Don’t wait it out.

Check out all the engine parts available on NAPA Online or trust one of our 16,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on engine placement, chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Photo courtesy of Wikimedia Commons.

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