What is a possible cause of white exhaust smoke?

White exhaust smoke is often indicative of a condition where coolant enters the combustion chamber. This typically occurs when there is a leak in the engine's cooling system, such as a blown head gasket, a cracked cylinder head, or a warped engine block. When coolant burns in the engine, it produces white smoke that can be observed coming from the exhaust.

Choosing the option that points to engine coolant leaking is correct because this is a common and critical issue that can lead to engine overheating and significant damage if not addressed promptly. The presence of white smoke serves as an alert that maintenance or a repair is needed to prevent further complications.

Other options, while related to engine performance and issues, do not specifically explain the occurrence of white smoke. For instance, excessive oil consumption may produce blue smoke from the exhaust, while improper fuel type could lead to different symptoms, such as poor combustion or knocking noises. Inadequate air supply generally results in black smoke due to incomplete combustion rather than white smoke.