Head gasket failure: a practical guide

The head gasket is a critical part in any vehicle engine. If it fails, it can cause serious damage if it is not spotted in time. In this guide we look at the most common symptoms of a damaged head gasket and how to identify them accurately.

What is the head gasket and why does it matter so much?

The head gasket seals the engine block and the cylinder head so that oil, coolant and combustion gases do not mix. When this gasket fails, unwanted fluid mixing and loss of compression can occur, which hurts performance and can lead to expensive repairs.

Main symptoms of a damaged head gasket

1. White exhaust smoke

If the coolant level keeps dropping with no external leaks found, the fluid may be entering the combustion chamber because of a head gasket failure. That produces dense white smoke from the exhaust pipe.

2. Oil and coolant mix (“mayonnaise”)

A frothy, milky-coffee substance on the oil dipstick or on the filler cap means oil and coolant have mixed, forming what is commonly called “mayonnaise”.

3. Oil in the expansion tank

If you see oil floating in the coolant expansion tank, it is a sign that engine oil has entered the cooling system, which can mean the gasket is damaged.

4. Overpressure in the cooling system

Excessive pressure in the cooling circuit, noticed as unusually hard hoses or constant bubbling in the expansion tank, can mean combustion gases are entering the cooling system.

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What should you do if the head gasket is damaged?

If you suspect a failure, it is crucial to act quickly to avoid greater engine damage. Specific tests are recommended, such as gas detection in the cooling system or compression tests, to confirm the diagnosis.

At Veiko we check every detail for you

At Veiko, every vehicle goes through a thorough technical inspection before it is auctioned. Our professionals inspect each unit rigorously and produce reports that tell the customer about any relevant issue, including possible signs of head gasket failure or any other component. That is how we guarantee transparency, trust and the best experience for our professional customers.