A vehicle's exhaust color can reveal problems in the combustion chamber. If the vehicle emits white smoke and continues to do so after startup, further inspection is required. This is because the engine's coolant is entering the combustion chamber and burning white when ignited.
This condition is often the result of an overheated engine. Overheating an engine can quickly warp a cylinder head and damage the head gasket. A crack in the cylinder head or engine block also causes this condition.
The intake manifold gasket on some engines can leak, resulting in coolant entering the chamber and burning white. Excessive oil burning in the combustion chamber results in blue-gray colored exhaust. Excessive fuel in the combustion chamber results in a rich air-fuel mixture and black-colored exhaust.