Does Engine Smoke Tell Us Anything About the Condition of the Vehicle Engine?

What Does Colour of Engine Smoke Mean?

The exhaust emissions of a perfectly tuned engine should be invisible; if the smoke of the engine is visible then there may be some defect in the engine. The colour of the engine smoke gives a clue to the possible engine defects. Some of them are discussed below:-

    1.      Thin White Vapours

This is due to condensation of water vapours inside the exhaust system and may be accompanied by a slow drip of water. It is perfectly harmless and is often seen during the starting of the vehicle from cold, in the morning.

    2.      Thick Blue or Grey Smoke

This may be due to the lubricating oil in the crank case reaching and burning in the combustion chamber. Apart from loss of oil, it can result in fouled spark plugs, rough idle, hard starting and sluggish acceleration. On turbo charged engines, bluish- grey smoke may mean failure of the turbocharger.

    3.      Black Sooty Smoke

Such a smoke is usually due to the air- fuel mixture being excessively rich. This may be due to many factors, e.g. a clogged cleaner, the choke stuck closed, a faulty sensor, a clogged component in the fuel injection system. The exact cause will need systematic investigation by a trained mechanic.

    4.      Thick White Smoke

This type of smoke indicates serious trouble and needs immediate attention. It may be caused by the burning of the coolant in the engine, a damaged cylinder head gasket, crack in the cylinder block or a damaged cylinder head. Any of these would require the complete engine overhaul. It is better and safer in such a case to tow the vehicle to the garage.