Symptoms suggesting a cracked cylinder head:
* Overheating: This is a major indicator. A cracked head allows coolant to leak into the combustion chamber or oil passages, affecting cooling efficiency and potentially causing the engine to overheat rapidly. Check your coolant level regularly. Low coolant without obvious external leaks is a huge red flag.
* White smoke from the exhaust: Coolant leaking into the combustion chamber will turn into steam and produce white smoke, often accompanied by a sweet smell (coolant is often sweetened). This is a strong indicator.
* Oil contamination with coolant (or vice-versa): Check your oil dipstick. Milky or frothy oil suggests coolant mixing with the oil. Similarly, examine your coolant reservoir; if it's oily or contains a milky residue, it indicates oil leaking into the coolant.
* Loss of compression: A crack in the cylinder head can cause a loss of compression in one or more cylinders. A compression test performed by a mechanic is necessary to confirm this.
* Coolant leaks: While external leaks are more readily apparent (look for dripping or puddles), internal leaks are harder to spot.
* Rough running engine: A crack might disrupt the combustion process, leading to a rough-running engine, misfires, or a loss of power.
Visual Inspection (Limited Effectiveness):
* Inspect the head gasket: While not directly the cylinder head, a severely blown head gasket is often *caused* by a cracked cylinder head or indicates a pre-existing weakness. Look for signs of leakage around the gasket during your visual inspection. This requires removing some parts (though this is beyond a DIY basic mechanic's skillset).
* Examine the head itself (if removed): A visible crack might be present, but they're often hard to find. They can be hairline fractures. Professional pressure testing is far more reliable.
Diagnostic Testing (Necessary for Confirmation):
* Pressure test: This is the most reliable method. A mechanic uses specialized equipment to pressurize the cooling system and check for pressure leaks indicating a crack.
* Leak-down test: This checks for leaks in the cylinders, which can reveal cracks affecting compression.
* Cylinder compression test: As mentioned above, this reveals if there's loss of compression, a symptom of a possible crack.
Important Considerations:
* DIY limitations: While you can check for some of the symptoms, accurately diagnosing a cracked cylinder head usually requires a professional mechanic's expertise and specialized tools.
* Cost: Repairing or replacing a cylinder head is a significant undertaking, often expensive.
* Engine damage: Ignoring a cracked cylinder head can lead to further and more extensive engine damage.
If you suspect a cracked cylinder head, do not continue driving the vehicle. This can worsen the damage and potentially cause catastrophic engine failure. Take it to a mechanic for proper diagnosis and repair.
