All vehicles have air filters to clean the air from harmful particles such as dust. An air filter is the first line of defense for your engine and the filter element which is usually paper-based is replaced when the vehicle gets a service. It is
well known that a dirty air filter which hasn’t been changed in a while will cause poor engine performance. When traveling in the outback, fine desert dust could potentially work its way through a standard paper filter if it’s already full of dust. Some argue that this dust can act as an abrasive on the cylinder walls and may also contaminate the engine’s oil.
A Diesel engine with a dirty air filter will pose a higher risk then a petrol engine because of the need for an obstruction-free smooth and clean air stream for the combustion chamber. The injectors will keep spraying the same fuel amount, so if the combustion chambers are not getting enough air, a richer mixture of diesel will spark. This will lead to a hotter than ideal burn in the combustion chamber, which of coarse is not good for any engine.