What does it mean when my car blows a head gasket?
A head gasket sits between the cylinder head and the engine block, the purpose is to seal the cylinders, the water/ coolant ports and the oil ports or jackets. The head gasket is a very crucial part of an engine as it has to seal a lot of pressure at the same time as sealing oil and water/ coolant whilst under high temperatures.
What are the signs and symptoms of blowing a head gasket?
There are several indications of head gasket failure which include;
- unexplained coolant loss- no visible leaks
- engine running hot or overheating
- white smoke coming from exhaust
- bubbling in radiator even when the system is cold
- milky oil when checking engine oil dipstick, showing that water/ coolant has mixed with oil
- running rough or engine miss firing
How do cars blow head gaskets?
The main cause of head gasket failure is due to engine overheating through loss of coolant, the extreme temperatures cause components to expand and expose weak spots in the gasket. Gasket design is also a cause as some are known to fail after a period of time or certain amount of kilometres. Design faults in particular models means that some models are more likely to fail than others, for example an aluminium cylinder head may crack before a cast iron cylinder head.
Is it expensive to repair?
Diagnosing and replacing a head gasket can be a costly exercise as it is very time consuming. It can also be difficult at times to diagnose and you need to be sure that all other components have been checked to ensure that it is definitely the head gasket that has failed. Removing and crack testing the cylinder head, machining, resetting valves and resealing the head all take a lot of time. If the cylinder head is cracked, which can be the case with a lot of aluminium heads, this will also add significantly to the cost.
Can you continue driving with a blow head gasket?
Ideally no you shouldn’t, but it depends on how badly the gasket has failed and in what area it has failed. The problem is only going to worsen and could eventually cause more issues. Initially it may be ok to keep driving if you keep an eye on fluid levels and engine temperatures, but the bottom line is a component has failed and you have water/ oil/ compression going into unwanted places and this will need to be rectified.
Will regular servicing prevent this?
Regular servicing may help to prevent this as fluid levels are checked and maintained at intervals. At the very least this could help identify the fault before it becomes a major problem.