Check a head gasket replacement quote

What the job usually involves.

The head gasket seals the joint between the cylinder head and the engine block, keeping combustion pressure, coolant and oil in their own passages. Replacing it usually means draining fluids, removing the intake and exhaust manifolds or disconnecting the exhaust, taking off the timing belt or chain and camshaft parts that are in the way on many engines, and lifting the head off the block.

With the head off, the shop usually cleans both surfaces, checks the head and the top of the block for flatness and the head for cracks. It then fits a new gasket and, on many engines, new head bolts tightened in the manufacturer's sequence and torque steps, before reassembly, fresh oil and coolant, bleeding of the cooling system and a pressure and road test.

Overheating is a common reason head gaskets fail. If the engine overheated, ask whether the quote also covers finding and fixing why, such as a leak, a cooling fan fault or a stuck thermostat, so the new gasket does not face the same conditions.

What a complete written quote should state.

• The tests the recommendation rests on, and their results.
• One cylinder head or both.
• Whether the head is checked, machined or pressure-tested, and by whom.
• New head bolts and any other single-use parts.
• Related parts replaced while the engine is open, such as a thermostat, water pump or timing parts.
• Coolant and oil, with the types named.
• Labor as hours or a flat price, shop supplies, disposal fees and tax.
• How added work found after teardown will be approved, and the written warranty.
• What was checked to find the cause of the failure, such as the cooling system, and any repair it needs.

SourceFederal Trade Commission — Auto Repair Basics ↗ (opens an external site)

What changes the total.

Engine layout matters most: an inline engine with one head and a V-shaped engine with two are different jobs, and on some vehicles much of the front of the engine must come apart to reach the head. Head machining or repair, if needed, comes next.

Related parts decided at the same visit, such as a timing belt or water pump, can add parts but reuse the same access labor. Gasket set grade, fluids, the local labor rate and tax account for the rest.

Gasket only, or head work too?

A gasket-only quote assumes the head and block surfaces are still flat and sound. If the head turns out to be warped or cracked, it may need machining, a pressure test by a machine shop or replacement, which changes the total after the engine is already apart. While the head is off, a valve job (reconditioning the valves and their seats) or new valve stem seals may be offered; ask what measurement or finding supports it.

Ask whether the quote includes checking and machining the head, and how the shop will handle added work. The FTC suggests the written estimate state that the shop will contact you before exceeding a set amount of time or money; state law may require this, and rules vary by state.

SourceFederal Trade Commission — Auto Repair Basics ↗ (opens an external site)

When a second opinion is worth it.

• Head gasket replacement is recommended without written test results.
• The quote does not say whether the head will be checked or machined.
• Only a sealer product is offered, with no explanation of what it can and cannot do.
• Engine replacement is recommended instead, without test results or teardown findings.
• The quote leaves out head bolts, fluids or related parts without saying they are reused.
• The quote does not mention checking why the engine overheated or lost coolant.

If the temperature gauge rises, the engine overheats or white smoke and coolant loss appear, stop driving when it is safe to do so. Overheating can damage the engine further, so ask whether a shop can inspect it after a tow.