* Cracked Cylinder Head: This is a common culprit, especially in older vehicles. The head gasket seals the coolant passages from the cylinders. A crack allows coolant to leak into the cylinders, mixing with the exhaust and creating white, often sweet-smelling smoke.
* Blown Head Gasket: Similar to a cracked cylinder head, a blown head gasket allows coolant to seep into the cylinders. This is a very common problem in high-mileage vehicles.
* Cracked Engine Block: Less common than head gasket or head issues, a crack in the engine block itself can also lead to coolant leaking into the cylinders. This is usually a more serious and costly repair.
* Coolant Leak into Exhaust Manifold: While not directly into the combustion chamber, a leak into the exhaust manifold can still produce white smoke as the coolant boils and turns to steam.
Important Considerations:
* Sweet Smell: If the white smoke has a sweet odor, it almost certainly points to coolant.
* Amount of Smoke: A small puff of white smoke on startup might be condensation, especially in cold weather. Persistent, heavy white smoke is a serious problem.
* Other Symptoms: Look for other signs like low coolant levels, overheating, milky oil (coolant in the oil), or a loss of compression. These symptoms help pinpoint the exact cause.
What to do:
Do not continue driving the vehicle with persistent white smoke. Continued operation can cause catastrophic engine damage. Have the vehicle inspected by a mechanic as soon as possible to diagnose and repair the problem. The longer you wait, the more extensive (and expensive) the repairs will likely be.
