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