Can You Still Drive a Car With a Blown Head Gasket?
Ellie Dyer-Brown, 9 months ago
5 min read
- Engine
- Repair
FixMyCar discusses what a head gasket is, what it does, and whether you can still drive when it breaks.
The head gasket is an important engine component. When it breaks, it can have serious - and expensive - consequences for the engine. That's why it's a good idea to familiarise yourself with what the head gasket does and the early signs of failure.
This guide covers everything you need to know.
Contents
What causes a blown head gasket?
In a nutshell: You shouldn't drive with a blown head gasket; doing so will cause more engine damage and could write your car off.
What is a head gasket?
You can find the head gasket between the engine block and cylinder. It's responsible for sealing the cylinders, preventing oil, coolant, fuel and air from mixing. This makes it the most stressed gasket in the engine.
In addition to stopping fluids from mixing, it allows them to flow freely in the correct areas, maintaining the correct temperature and keeping the right parts lubricated.
What causes a blown head gasket?
Overheating is the most common reason for a blown head gasket. Excessive heat can cause warping and cracking in the engine block, which prevents the gasket from maintaining a tight seal.
Problems during pre-ignition can also impact the head gasket. When fuel is combusted at the wrong time, it puts immense pressure on the cylinder head, often resulting in perforations down the line.
Similarly, when a head gasket hasn't been installed correctly, it's likely to blow, though it might take a while. The head bolts must be turned so that they are neither too tight nor too loose, which can be tricky to get right.
Symptoms of a Blown Head Gasket
Coolant in the oil
Corrosion on the surface of the head gasket
Coolant on top of the spark plugs
Increased engine running temperature
Bubbles in the radiator and reservoir flow
The oil under the fuel cap has a milky discolouration that resembles mayonnaise
How to check the head gasket
The head gasket is hard to access in the engine bay, so it's difficult to visually assess its condition. Fortunately, there are a few checks you can perform to detect emerging head gasket issues.
Look under the oil filler cap. If you notice a milky-looking substance, this indicates that coolant has leaked into the oil, which is a sign of head gasket failure.
Check for leaks. Leaking oil and coolant could be coming from a faulty head gasket.
Inspect the coolant tank. Again, look out for a milky-white substance.
Check the colour of your exhaust smoke. Excessive white smoke happens when coolant is burnt in the combustion chamber.
Fluid leaks and white exhaust smoke can have various causes; the most conclusive sign of head gasket failure is a milky substance in the coolant reservoir or under the oil filler cap.
Can you drive with a blown head gasket?
When your head gasket blows, your car will immediately lose power, and leaking coolant means the engine is far more likely to overheat, causing more problems.
Whether you can continue driving and whether you should are two very different things.
We strongly recommend not driving when your head gasket has blown. If you start encountering any symptoms described above, you should seek mechanical assistance immediately.
It can be tempting to put repairs off due to fears about the costs. However, continuing to drive could lead to extensive damage to your car’s other components and the engine, including parts like the catalytic converter, which will cost much more than a head gasket repair.
If you think your car's head gasket has blown, FixMyCar is here to help you find the best price for a top-quality repair.
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Written by Ellie
Ellie is FixMyCar's Content Writer. She has over three years of experience writing about cars and regularly collaborates with automotive experts to provide trustworthy advice for drivers that is easy understand. Her work has been featured in Yahoo! Finance, iNews, The Daily Express and The Sun. She has a BA in English literature and an MA in creative writing from Durham University. Outside of work, Ellie follows F1 and eagerly awaits Ferrari's next era of dominance in the sport. She drives a Suzuki Swift.