Visual Inspection (Easier, less definitive):
* External Examination: Carefully inspect the cylinder head itself (if you've removed it). Look for obvious cracks, especially around the bolt holes, valve seats, and coolant passages. Use a bright light and a magnifying glass if necessary. Even small cracks can be significant. Pay close attention to any areas where corrosion might be hiding a crack.
* Coolant System Inspection: Look for signs of coolant leaks around the head gasket area. White milky residue (indicative of oil and coolant mixing) on the oil fill cap or dipstick is a strong indication of a potential head gasket failure, which often accompanies a cracked head. However, a leaking head gasket doesn't *guarantee* a cracked head; it could be just a blown gasket.
* Exhaust System Inspection: Look for excessive white smoke from the exhaust (especially when the engine is cold), which can indicate coolant leaking into the combustion chamber – a symptom of a cracked head.
Testing (More definitive, often requires tools):
* Pressure Test: A pressure test of the cooling system is crucial. If the pressure drops significantly over time without visible external leaks, it strongly suggests a crack within the head or block. This requires a pressure tester and is best done by a mechanic.
* Leak Down Test: This test pressurizes each cylinder individually and measures the air escaping. Excessive leakage can indicate a crack in the head or a severely damaged head gasket. This requires a specialized leak down tester.
* Dye Test: A dye can be added to the cooling system. After some running time, UV light can be used to detect any leaks, even very small ones.
Important Considerations:
* Head Gasket vs. Cracked Head: A cracked head is a much more serious problem than a blown head gasket. Often, the symptoms are similar. A pressure test is critical to distinguish between the two.
* Professional Diagnosis: Accurately diagnosing a cracked cylinder head is difficult. Unless you have significant mechanical experience and the proper tools, it's best to take your Corsica to a qualified mechanic for a proper diagnosis and repair. They have the equipment and expertise to perform the necessary tests.
* Cost: Repairing a cracked head is expensive, often involving machining, replacement, or possibly even a complete engine rebuild. It may be more cost-effective to replace the entire engine depending on the extent of the damage and the car's overall value.
In short: Visual inspection can point towards a problem, but definitive diagnosis requires pressure testing or a leak-down test performed by a mechanic. Don't attempt major repairs yourself unless you have the appropriate skills and tools.
