* White Smoke: White smoke, especially on startup, usually indicates burning coolant. Unlike blue smoke (oil burning) or black smoke (rich fuel mixture), white smoke is often a telltale sign of coolant entering the cylinders.
* Rough Idle: Coolant in the cylinders disrupts the normal combustion process, leading to a misfire and a rough, uneven idle.
Possible Causes of Coolant Leak into Combustion Chambers:
* Cracked Cylinder Head: This is a common culprit. Over time, pressure and heat can cause cracks in the cylinder head, allowing coolant to seep into the cylinders. This is especially likely given the age of the vehicle.
* Blown Head Gasket: A failing head gasket is another major possibility. The head gasket seals the cylinders from the coolant passages, and a breach in this seal allows coolant to leak into the cylinders. This is also a very common problem in older vehicles.
* Cracked Engine Block: Less common, but possible. A crack in the engine block itself could also allow coolant to mix with combustion. This is usually a more serious and expensive repair.
* Other less likely, but possible, causes: A severely warped cylinder head (requiring machining or replacement), or a coolant leak into the intake manifold (potentially from a cracked intake manifold or other seal) could also contribute to similar symptoms.
What to do:
It's crucial to address this immediately. Continuing to run the engine with coolant leaking into the cylinders can cause significant damage, including:
* Severe engine damage: Hydrolock (coolant filling the cylinders) can bend connecting rods or other internal components.
* Catalytic converter damage: Coolant in the exhaust can damage or destroy the catalytic converter.
Next Steps:
1. Stop driving the car immediately: Continued operation risks catastrophic engine damage.
2. Have a qualified mechanic diagnose the problem: They can perform a pressure test on the cooling system and a compression test on the cylinders to pinpoint the source of the leak. Visual inspection might also reveal external leaks.
3. Get the necessary repairs performed: This could involve replacing the head gasket, repairing or replacing the cylinder head, or, in a worst-case scenario, engine repair or replacement.
Don't attempt to diagnose or repair this yourself unless you have extensive experience working on engines. The consequences of an incorrect diagnosis or repair could be very costly.
