Head Gasket Buying Guide
Ultimo aggiornamento: 24 aprile 2026
The cylinder head gasket seals the joint between the engine block and cylinder head, containing combustion gases, coolant, and oil within their respective passages. A blown head gasket causes overheating, white exhaust smoke, coolant loss, and can lead to catastrophic engine damage if not addressed promptly.
Head gasket failure symptoms
Head gasket failure can be caused by overheating, age, or a warped cylinder head. Symptoms range from subtle coolant loss to severe overheating and engine seizure.
- White smoke from the exhaust (coolant burning in the combustion chamber)
- Coolant level dropping with no visible external leak
- Milky emulsion under the oil filler cap (oil/coolant mixing)
- Engine overheating or temperature gauge fluctuations
- Bubbles in the coolant expansion tank (combustion gases entering the cooling system)
Replacement considerations
Head gasket replacement is a major job. The cylinder head must be removed and inspected, and often skimmed to restore flatness.
- Always have the cylinder head checked for warpage and crack-tested before refitting
- Replace head bolts — most modern engines use stretch bolts that must not be reused
- Follow the manufacturer's torque sequence and values precisely
- Flush the cooling system to remove any oil contamination
- Replace the thermostat, coolant hoses, and cambelt if due while the engine is apart
Category page
- Browse matching parts
Overheating, milky oil, and white exhaust smoke — identifying a blown head gasket, multi-layer steel vs composite types, and what the repair involves.
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- Crankcase Ventilation (PCV) Valve Buying Guide
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- Crankshaft Position Sensor Buying Guide
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- Engine Oil Pump Buying Guide
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Domande frequenti
How much does a head gasket replacement cost?
The gasket itself is relatively inexpensive, but labour is intensive — typically 8-15 hours. Expect to pay for head skimming, new bolts, and associated gaskets. Total cost varies widely by vehicle.
Can I drive with a blown head gasket?
No. Continued driving risks severe overheating, coolant entering the oil (destroying bearings), and hydro-locking the engine if coolant fills a cylinder.
What causes a head gasket to fail?
Overheating is the most common cause. Coolant loss, thermostat failure, radiator blockage, or a faulty water pump can all cause overheating that warps the head and blows the gasket.
Do head gasket sealers work?
Chemical sealers are a temporary measure that may seal minor leaks but cannot fix a severely blown gasket. They can also block heater cores and radiator passages. Proper replacement is the only reliable fix.
Guide correlate
P0340 fault codes, misfires, and rough running — how camshaft sensors control valve timing and when to replace them.
Crankcase Ventilation (PCV) Valve Buying GuideOil leaks, high oil consumption, and rough idle — how the PCV valve prevents pressure build-up, clogging symptoms, and easy replacement steps.
Crankshaft Position Sensor Buying GuideNo-start, misfires, and sudden engine cut-out — how the crankshaft sensor works, fault codes, and choosing the correct replacement.
Engine Oil Pump Buying GuideLow oil pressure warning, noisy engine, and bearing wear — oil pump failure causes, pressure testing, and what to do when the pick-up tube is clogged.
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