Introduction to head gaskets
What is a head gasket? A head gasket is a seal, normally consisting of multiple layers of steel, which seals your cylinder head to your engine block.
Other than sealing the two major components together it also keeps oil & water passages separate along with sealing the combustion chamber
Why does it fail?
Whilst engine age & milage can be a contributing factor, most head gaskets fail after an episode of overheating the engine block causing warpage to the cylinder head.
Another failure point here in Zimbabwe is lack of coolant use. Many “mechanics”, hobbyists & general motorists here in Zim believe a coolant system only requires water & they certainly think the cooling system doesn’t require servicing (see our post on that here!) eventually corrosion takes hold of the waterways or the gasket material itself causing failure that leads to overheating or coolant & oil mixing.
Other less common failure points are improperly torqued cylinder head bolts, cracks to the head or block or premature ignition causing higher combustion pressures.
Symptoms of a failed gasket
- White exhaust smoke, coolant loss & oil contamination
- Overheating, power loss & rough running
- Heating issues noticed in the cabin
Repairing a blown gasket
A blown head gasket is often a labour intensive job and usually requires a machinist to true (make flat) the cylinder head. Most vehicles would factor in 6 – 10 hours of labour & a few days for the head work to be completed at the machine shop. Machine shop rates change but generally your looking at around $150 – $200 for a head skim
What else is involved
- Removing engine covers from the top and front
- Removing the timing belt or chain assembly (would recommend replacement)
- Removing valve covers, camshafts and sometimes valves
- Removing the remaining head assembly
- Rebuilding with new high quality gaskets & seals
Prevention of head gasket problems
Preventing a head gasket failure is often just done by routine maintenance. Servicing & inspection can pick up early signs of problems which may lead to gasket failure. Servicing your cooling system at manufacturer recommended intervals is advised to stop premature failure.
Any signs, however slight of overheating should be checked by a qualified mechanic as this can cause failure if allowed to continue.
Unless in a complete emergency mechanic.co.zw would never recommend the use of head gasket/radiator stop leak cans. These often cause much larger problems down the road by blocking coolant passages and radiators leading to further cooling problems.
Conclusion
If you suspect you have a head gasket problem, heating problem or just require servicing get in contact with mechanic.co.zw without delay for a free quote and at home mobile service!
Leave a Reply