What Causes a Blown Head Gasket?

by James Norbeck

The head gasket is a seal that joins the engine head with the cylinder. When the engine overheats, the metal expands and damages the gasket. Overheating prevention is a critical part of vehicle maintenance and operation.

TEMP Warning Light

If the vehicle's TEMP light is on, pull over and stop the engine. The TEMP light means the engine is being damaged. Blown head gaskets are usually the first problem caused by overheating.

Watch for Leaks

Check for fluids dripping from the vehicle. Coolant can be green, yellow or orange. If your car loses enough coolant, it will overheat. Check for broken hoses or clamps. A leak that originates from the engine itself usually indicates water pump failure.

Check Coolant Level

Most vehicles have a semi-transparent coolant reservoir that indicates fluid level. If the reservoir is completely empty, fill the radiator first, then the reservoir. Recheck the reservoir after driving 10 minutes. Never open the radiator until the engine is cool.

Don't Ignore Steam

Steam under the hood usually means coolant is leaking. If you see steam or smell coolant, pull over and stop the engine. Catching a coolant leak before the engine overheats could save thousands of dollars.

Test and Replace Coolant

As coolant ages, it loses its ability to cool the engine, fight corrosion and resist freezing. Worn-out coolant can cause overheating even if the cooling system is working.

50/50 Mix

Antifreeze must be diluted with an equal amount of water. Use distilled water; tap water causes corrosion. Premixed antifreeze is also available.

About the Author

James Norbeck is a freelance fitness, lifestyle, and technology writer and award-winning filmmaker from Portland, Oregon. His career began as a television news writer in 1990, and his writing has appeared in “FUEL” magazine. He holds a Bachelor of Arts in communications from Portland State University.