What Are the Signs of a Blown Head Gasket?

What the head gasket does

The head gasket is a seal between the top of the engine (the cylinder head) and the main block. It keeps combustion pressure in the cylinders and stops coolant and oil mixing or leaking out.

When it fails, usually after the engine has overheated, those fluids and gases end up where they should not.

The classic symptoms

Watch for thick white exhaust smoke with a sweet smell that does not clear once the engine is warm, coolant disappearing with no visible leak, and the engine overheating.

Other signs are bubbles in the coolant expansion tank with the engine running, coolant hoses that go rock hard, the engine running rough when first started, and loss of power.

Things that look like a head gasket but are not

A little white vapour from the exhaust on a cold morning is normal condensation and clears as the car warms up. A creamy residue under the oil filler cap can also be condensation, particularly on cars that only do short journeys.

Coolant loss can come from a leaking hose, radiator or water pump. That is why testing matters before anyone quotes for a head gasket.

Stop driving if you suspect it

Carrying on driving with a failing head gasket can warp the cylinder head and damage the engine beyond economical repair. If the car is overheating or losing coolant fast, park it and get it checked.

Caught early, a head gasket is a repairable job. Left too long, it can end the engine.

Testing and repair in Smethwick

At ER Automotive we confirm the fault first with a combustion leak test and pressure tests. If the gasket has gone, we check the cylinder head is flat and skim it if needed before refitting. Call 0121 461 6097 or book online.