WHITE, GREY, BLUE OR BLACK : WHAT DOES MY CAR'S COLORED EXHAUST SMOKE MEAN ?

Vehicles with engine problems may exhibit a variety of symptoms. It may appear in many different forms, such as noise, vibration, or colored exhaust. High exhaust emissions of any color indicate an engine problem, something bad happened to your cars mechanicals which may be caused due to fluid leakage inside the engine. Depending on the color of the smoke, you can usually determine what kind of problem occurred. There are the four most common exhaust colors that vehicles emit. Which are White, Grey, Blue or Black.

How to diagnose the problem ?

First of all you have to find out when the colored smoke starts to emit once car is started. It may be while accelerating or in stationary conditions. Next, you have to find out what color the smoke is ? Is it White ? or is it Black ? or is it Blue or Grey ? Okay. Now you have found what color the smoke is. Lets dive in to details what causes these different colored smoke emissions.

White exhaust smoke

This is the most common type of smoke problem found in cars and it really is steam. Steam is a bi-product of hydrocarbon burning cycle and once the engine warms up this steam evaporates quickly. But the problem occurs when this steam doesn’t go away even after engine runs for a while. So, the problem could the coolant leakage into the engine due to a damaged gasket.

Black Exhaust smoke

Black smoke means your engine is burning too much fuel while intake air is not enough to completely burn the fuel. Most common cause for this is clogged air filter. Other causes may include leaking fuel injectors, malfunctioning fuel pressure regulator or a blockage in the air intake pipe.

Grey exhaust smoke

This is due to excess of oil is burning in the engine. This might cause due to the fault in Positive Crankcase Ventilation (PCV) which controls the emission as it draws back unburnt fuel from lower sections of the engine to the top. If it is a car with automatic gearbox another reason for grey smoke could be the leakage of transmission fluid to the engine.

Blue exhaust smoke

As in grey smoke, blue exhaust smoke could be a sign of the leakage of engine oil to the system. The role of engine oil is to lubricate the moving parts in the engine like pistons and normally the engine oil doesn’t enter to the fuel system. If your vehicle covered a high mileage this could be a result of worn out piston rings, gaskets or valve seals. So, the repairs will be costlier but definitely needs attention because this might cause huge damage to the engine soon.

In summary these are the causes for different colored exhaust smoke :-

• White exhaust smoke : Condensation of steam or coolant leakage to the engine

• Black exhaust smoke : Burning excessive amounts of fuel

• Blue or Grey exhaust smoke : Engine oil is leaking into the system