Good question. I've seen engine fires caused by fuel leaks and by electrical wiring that has failed and ignited surrounding material.

CAUSED by fuel leaks.

Car-B-Que

Do you mean caused by? Overheating/ leaks..

I assume you mean "caused" by... Usually it's overheating.

The Fire Triangle! Fuel- oil, gas, diesel, rubber, plastic, etc. + Heat- engine overheat, electrical short, friction sparks. + Air. Ta-Daa!