What's involved
What this repair actually is.
The head gasket seals combustion pressure, coolant, and oil between the engine block and cylinder head. When it fails — usually after overheating — coolant and combustion gases mix, causing white smoke, milky oil, and chronic overheating. The engine's top end comes apart, the head is checked (and often machined flat), and everything is reassembled with new gaskets and bolts.
Symptoms
How you can tell.
- White sweet-smelling smoke from the exhaust
- Coolant disappearing with no visible leak
- Milky, coffee-colored oil on the dipstick or cap
- Repeated overheating
- Bubbles in the coolant reservoir with the engine running
If you delay
Continuing to drive warps the cylinder head and can hydrolock or seize the engine, turning a head gasket job into a full engine replacement.
Educational estimate. Real pricing depends on your vehicle, the inspection, parts availability, taxes, and shop rates. Use this as a guide while you shop quotes.
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