Diagnosing Problems with a Smoking Exhaust Pipe
A smoking car exhaust can denote several possible mechanical faults. As a rule of thumb a smoking exhaust isn’t good news and is unlikely to be something simple unless it is caused by a fuel problem. A smoking car is hard to diagnose as there are many faults which cause anengine to smoke.
Before examining different faults diesels that have not been serviced regularly can belch out black smoke when accelerating hard. The smoke usually clears when the car is no longer labouring. The problem is simply cured by having the car serviced according to the manufacturer’s guidelines.
Petrol cars that belch out black and blue smoke may simply be running rich and the fuel delivery system needs to be looked at. This is a relatively minor problem. Run a finger inside the end of the tail pipe and if your finger is coated with thick black carbon will confirm the possibility the car is running rich.
Heavy black blue pungent smoke is more likely the result of a much worn engine. The smoke is where oil is burning with petrol. One might notice a peculiar smell this will be piston rings breaking up in the cylinders. Open the hood and if the smell is radiating from the engine will add to the suspicion the engine is badly worn. This will only affect elderly or badly handled cars.
White smoke can suggest he fuel is too weak and again the fuel delivery system needs looking at. The car will also be running rough and not as smooth as one would expect.
If the smoke is white, blue and black accompanied by the car overheating will almost certainly suggest a blown head gasket. If the car is hard to start may confirm suspicions of a faulty head gasket. Go to the back of the car and run your finger inside the tail pipe. If your finger has oil on it, the head gasket has failed. If your finger is wet this too will suggest the head gasket has failed. This happens because the gasket has failed allowing either oil or water and sometimes both to mix with burnt fuel. A head gasket is an expensive repair.
Black smoke can also be attributed to a faulty turbo charger. The smoke will be continuous and thick regardless of driving conditions. A replacement turbo charger is an expensive repair. If your car is not fitted with a turbo charger the fault must lie elsewhere.
