Performance Issues:
* Loss of power: The engine may struggle to accelerate or maintain speed.
* Overheating: This is a classic symptom, as coolant leaks into the cylinders or oil. The temperature gauge will climb rapidly.
* Rough running or misfires: Coolant leaking into the cylinders disrupts the combustion process.
* Reduced fuel efficiency: A combination of the above issues leads to less efficient engine operation.
Visible Signs and Leaks:
* White smoke from the exhaust: This is a major indicator, caused by coolant burning in the cylinders. The smoke may also smell sweet.
* Coolant in the oil: This is often seen as a milky, mayonnaise-like substance on the dipstick or in the oil filler cap.
* Oil in the coolant: The reverse of the above; oil contaminates the coolant reservoir.
* External coolant leaks: Though not always present, a blown head gasket may cause visible coolant leaks around the engine block.
Other Symptoms:
* Low coolant level: Consistent loss of coolant without visible leaks points towards internal leakage.
* Compression test failures: A compression test will show low compression in one or more cylinders if the gasket is blown.
* Bubbling in the radiator or coolant reservoir: This indicates combustion gases entering the cooling system.
* Engine knocking: This could be a result of the engine running lean due to air leaks or coolant entering the cylinders.
It's crucial to note that some of these symptoms can be caused by other problems as well. A proper diagnosis by a qualified mechanic is necessary to confirm a head gasket failure before undertaking the expensive repair.
