- Coolant leaking into the combustion chamber: In some cases, a blown gasket or a cracked cylinder head can cause coolant to leak into the combustion chamber. This coolant then becomes vaporized and exits through the exhaust pipe as white smoke. The most telling sign that this particular issue is the cause is that the smoke will smell distinctly sweet.
- Fuel not being completely combusted: If the engine is running too rich, it is possible that not all the fuel will be completely burned off. The unburned fuel will then travel through to the exhaust system, where it will be heated up and turn into white smoke. One indicator that this could be the issue is that the smoke will often have a strong smell of fuel.
- Water vapor: In cold or humid weather, water vapor can sometimes condense in the exhaust system and come out as white smoke. This is especially prevalent when the engine is first started. This smoke will usually dissipate quickly as the engine warms up.
