1. Coolant Loss or Leaks
Visually check for leaks under the car, check the water pump for loose seals, and the actual internal coolant level for significant drops in coolant level.
2. Air Bubbles in Radiator
Check for air bubbles coming up through the radiator. This causes pressure in all the wrong places and can either signify or cause head gasket problems. Sounds silly but remember to remove the cap and ensure the engine is cold before checking this.
3. Engine Overheating
Keep an eye on your temperature gauge. Don’t leave it to the heat warning; this probably means it’s too late and can cause some serious damage to the engine.
4. Engine Running Rough
Is it sluggish or “chuggy” (both technical terms of course), or maybe a loss of power? A blown head gasket prevents an engine from performing as it should.
5. Contaminated Spark Plugs
Remove a spark plug (when the engine is off) and visually check to confirm oil on the threads or around the plug.
6. Smokin’
Look for white smoke or liquid exiting the exhaust, or loosing coolant through the overflow. To check this remove the cap (when cold) and rev the engine. If you see bubbles or any exits you will notice.
7. Oil and Coolant Shouldn’t Mix
Oil floating in the water in your cooling system. There can be water in your oil too.
8. Icky Sludge in Oil
Use your dipstick (no, the other one) to inspect the consistency and colour of the oil.
9. Hoses Deteriorating or Becoming Detached
Visually check any hoses or pipes around the engine, looking for wear, hoses appearing thin or worn, or becoming detached completely, apparently of their own accord.
10. Low Compression
Take the vehicle to a professional mechanic for a compression test or general head gasket diagnosis.