Common Symptoms of a Blown Head Gasket:
* White or milky-colored substance in engine coolant: This indicates that oil and coolant are mixing. Check the coolant reservoir cap for this residue.
* Oil that looks like chocolate milkshake: Again, this points to coolant mixing with the oil, due to a leak between the cylinders and the cooling passages. Check your dipstick.
* Overheating: A blown head gasket can restrict coolant flow, causing the engine to overheat. This is often accompanied by the steam or white smoke from under the hood.
* Loss of coolant: Check your coolant reservoir regularly. If it's constantly low, even after you've refilled it, it's a strong indicator of a leak. Look for puddles of coolant under the car.
* Compression test shows low compression in one or more cylinders: This is a more definitive test that needs to be performed by a mechanic. It directly measures the pressure within each cylinder. A significant drop in compression in one or more cylinders suggests a leak, potentially from a blown head gasket.
* Exhaust bubbles in the coolant: This is a more advanced test requiring a pressure tester connected to the radiator. Bubbles in the coolant indicate combustion gases leaking into the cooling system.
* Sweet-smelling exhaust: Coolant is mostly water, but it also contains anti-freeze with a distinctively sweet smell. If you detect this sweet odor in your exhaust, it suggests a leak into the combustion chamber.
* Engine misfires or rough running: This could be due to several reasons, but a blown head gasket can lead to misfires by leaking compression.
Important Considerations:
* Other causes: Some of these symptoms (overheating, loss of coolant) can also be caused by other problems, such as a cracked radiator, a leaking hose, a faulty thermostat, or a failing water pump.
* Professional Diagnosis: While you can check many of these symptoms yourself, a proper diagnosis often requires a compression test, a leak-down test, or a pressure test, all best performed by a qualified mechanic. These tests will help pinpoint the exact problem and confirm if it's a blown head gasket.
In short: Don't jump to conclusions. If you suspect a blown head gasket, start by carefully observing the symptoms listed above. If multiple symptoms are present, especially the oil/coolant mixing, it's highly probable, but you'll want a mechanic to confirm with a proper diagnostic test before investing in a costly repair.
