Smoke from exhaust pipe
Such a thing as the color of the exhausts’ smoke can provide a lot of useful information about your car. It helps to prevent serious damage. Under normal conditions, the smoke is almost colorless.
Black smoke - not as dangerous as it seems
Indeed, the black color of smoke is not a sign of a critical problem, but it shouldn't be ignored, because at first a slight dysfunction of the car can develop into a breakdown that requires an expensive solution.
Cause: a rich fuel mixture.
So, the fuel mixture doesn’t burn completely and the excess goes through the exhaust. About how it affects, you can read here. The source of the fuel concentration changes is different for engines.
Carburetor engine - no longer used. However, the blame for the formation of black smoke, in this case, falls on: a weak needle valve and washed down jets.
For an injector engine, the problem is in the injector itself. Standard cleaning, will solve the problem. In addition, the work of this motor is tied to electronics, the errors in the system, the waste of contacts, violations in the sensors - can lead to a high concentration of gasoline in the fuel mixture.
For diesel engine, whiter dark smoke is a normal condition. That happens due to the fact that the fuel itself is low-volatility. However, it is important to clean the particulate filter to reduce black smoke.
White smoke - mostly is OK
Dense white smoke, can be a variant of the norm too. Actually, it isn’t difficult to determine it as a sign of a problem in any car system.
Reason 1: Water vapor in a cold campaign. The air in the engine is actively condensed due to changes in temperature. However, after a long trip and warming up the engine, the exhaust becomes more transparent. Bring a sheet of paper a few inches from the exhaust. If the paper gets wet, it's just water.
Reason 2: If the white smoke from the exhaust appear as well as a problem of engine rotational rate fast changes, you need to drive to the service center immediately. It means that the coolant gets into the combustion chamber together with the fuel. Which comes out through the exhaust pipe, staining the exhaust gas in white. If you run this process, you may be faced with a major overhaul of the engine.
Blue smoke is definitely a negative symptom
Blue smoke indicates oil entering the combustion chamber. As a result, the engine misfires, moreover, it will be difficult to start the car? The effects touch many auto systems ranging from candles to catalyst failure.