White Smoke Problems--Identifying 4 Common Causes from Bad to Worst

Have you ever seen white smoke come out from your exhaust pipe? You've probably been told that this is a worrying sight, but before you panic, you’ll want to see if it clears up after a minute or so. If it does, it may simply be harmless condensation. That white smoke is just the warm hot air from the engine meeting the cold outside air.

But what if you see white smoke all the time? That's a sign of a simple or very serious problem. Take a look at four of the leading causes of white smoke coming from your exhaust, arranged from bad to worst.

Malfunctioning ECU

The engine control unit (ECU) is your engine's brain, and if there's something wrong with it, the timing of the combustion can be thrown completely off. If your ECU is the culprit, it will need to be reprogrammed by a trained technician. The good news is you won't have to spend for parts replacement when this is the cause of your white smoke problem. That is, unless the ECU itself needs replacing.

Faulty fuel injector

The fuel injector is the component in charge of sending fuel into the internal combustion chamber. It must do this at precisely the right time, or the engine will be out of timing. If an improper amount of fuel did not enter the chamber at the time of combustion, white smoke will occur. This particular problem more commonly happens in diesel engines. Fortunately, fuel injectors are fairly cheap and easy to replace.

Worn piston ring or valve seal

The seals found around the piston rings and valves help keep the engine oil from entering the combustion chamber. When these go bad, the oil will mix with the fuel and burn along with it, leading to white smoke. Replacing these seals involves a top overhaul, which is fairly intensive work, consequently making it an expensive one as well.

Damaged cylinder head

This is the worst possible cause for white smoke, as it almost always requires the replacement of the head itself. When your cylinder head gets cracked or damaged, coolant can begin to leak internally. Even the tiniest crack can cause coolant to leak into and mix with the engine oil, thus contaminating it. Contaminated engine oil is what's causing the white smoke from your pipe. This is accompanied by a sweet odor that's characteristic of engine oil.