Head Gasket Replacement

The head gasket is located between the engine's cylinder head and block. When a spark ignites gasoline in the engine, the explosion creates pressure in the engine. The head gasket provides a seal that keeps that pressure contained within the engine's cylinder. The head gasket also provides a seal for internal engine water and oil passages.

If the engine is allowed to overheat, the cylinder head gasket may become damaged. Running the vehicle when its coolant is low or when there has been a cooling system failure can cause overheating.

Replacing the head gasket requires major engine dismantling. The cooling system is drained, and the intake and exhaust manifolds are removed. The timing cover, timing belt (or timing chain), and valve covers may also need to be removed. In order to gain access to the bolts and hardware securing the cylinder head to the engine block, the camshafts may need to be removed.

After the cylinder head is removed, the cylinder head and engine block surfaces are cleaned and examined for damage. The head gasket is replaced and engine components reassembled.

Mechanics' Corner: More Technical Detail

Head gasket failure caused by severe or repeated engine overheating will necessitate close inspection of the cylinder head itself for cracks, as well as measurements taken to assure that the cylinder head is not warped. A warped cylinder head can often be machined flat, but it may have to be replaced.

Due to the damaging effects of coolant entering the combustion chamber, oxygen sensor and/or catalytic converter replacement may be prudent or even necessary. This is especially true if head gasket failure was severe or prolonged.

7 User Comments

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Thanks for the in-depth overview on gasket repair it was very helpful.
Great information. I am curious why my head gasket could have failed. I am the original owner of 2004 Nissan Frontier with 31k miles. Could it be a manufacturer defect? No other potential causes seem to apply to me.
Thanks for the great info!
My 2002 Olds Silhouette AWD needs a head gasket. The fix it price is $2500, as they'll do both, not just one. A just in case senario. Does that seem normal? I have approved it, so this is matter of fact question. Thanks
BTW, I have a Cadillac with 50000 miles on it that recently had the same head gasket problem as the Olds Minivan(Different dealership)Thinking GM has this problem over the entire line.
The older GM engines 3.1L up to the 4.0L were very fickle about intake and head gasket failure..
i need to get the information how to torque the head for my car it is a 2001 chevy malibu 3.1 litter