The heart of an engine's lubrication system is the oil pump. It sucks oil in from the crankcase and pushes it through the filter and oil galleries to the bearings, camshaft and upper valvetrain. A steady supply of lubricant is absolutely essential to prevent metal-to-metal contact, wear and friction between moving parts, to help cool the bearings and pistons, and to maintain proper valvelash in engines that have hydraulic lifters or cam followers. If for any reason the pump cannot keep the oil circulating, it's bad news for the engine. The first symptom of low oil pressure is typically valve noise and/or a warning light or low oil pressure gauge reading usually at idle. From here, things can quickly take a turn for the worse. Loss of oil pressure may starve the bearings of their much-needed lubrication. With no oil to keep the surfaces apart, bearings can wipe and fail. A seized rod bearing will often break the connecting rod and put it through the side of the engine block. A seized main bearing will often spin and wipe out the main bore.

An oil pump failure is like cardiac arrest because the results are often fatal.

Nothing Lasts Forever
With regular oil and filter changes, an original equipment oil pump should last the life of the engine. Today, that means upwards of 150,000 miles or more. But some oil pumps may not go the distance because the pump is the only internal engine component that runs on unfilter...