* Oil burning. This is the most common cause of dirty white smoke. When oil leaks into the combustion chamber, it burns and produces white smoke. This can be caused by worn piston rings, a bad valve stem seal, or a cracked cylinder head.
* Coolant burning. Coolant can leak into the combustion chamber through a blown head gasket or a cracked cylinder head. When coolant burns, it produces steam, which appears as white smoke.
* Fuel injector problems. If a fuel injector is leaking, it can cause the engine to run rich, which can produce white smoke.
* Air leaks. Air leaks can cause the engine to run lean, which can also produce white smoke.
If you're experiencing dirty white smoke coming from the exhaust, it's important to have the vehicle inspected by a qualified mechanic to determine the cause.
Here are some additional things to consider:
* The fact that the smoke only happens occasionally suggests that it's not a major problem.
* The fact that the smoke is only visible when pulling long hills suggests that it's related to the engine working hard.
* The fact that the performance gauges are all reading fine suggests that the engine is not overheating or experiencing any other major problems.
Based on this information, it's possible that the dirty white smoke is caused by a minor oil leak. However, it's important to have the vehicle inspected by a mechanic to be sure.
