The severity of a vehicle’s oil leak depends on several factors, such as the location of the leak and its size. Obviously, a major oil leak will lower your oil levels faster, and lead to other, more serious problems. For small leaks, the location matters the most, as a leak from the front crank seal or the timing cover will shorten the life of the timing belt or engine drive belts, while a valve cover gasket leak will get oil on the hot exhaust manifold, potentially causing smoke or even fire.