The oil pump (or engine oil pump) is a critical component of the lubrication system in any internal combustion engine. It ensures the forced circulation of motor oil through the lubrication system, delivering it to the bearings of the crankshaft and camshaft, as well as other engine components that require pressure-fed lubrication. To provide reliable lubrication to friction pairs, the oil pump must circulate the entire volume of oil several times per minute. Additionally, after the engine has been idle for an extended period, the pump must quickly deliver oil to friction points as soon as possible.

Typically, automotive oil pumps are gear-type, using external or internal gear engagement, and are usually driven either directly or through an intermediate transmission (gear or chain) from the engine’s crankshaft. The pump housing is usually made of aluminum alloys, while the gears and drive shafts are made of steel. Most oil pumps also include a pressure relief valve, which is crucial for maintaining the proper functioning of the engine’s lubrication system.

While oil pumps are generally very durable, they do eventually wear out—especially the gears and their housing. One sign of such wear is the flickering of the red oil pressure warning light on the dashboard, indicating that the oil pressure in the lubrication system has dropped to an unsafe level for engine operation. If the oil pump is not replaced in time, the engine’s main and rod bearings will inevitably fail, and even the crankshaft itself may become damaged beyond repair.

Therefore, replacing the oil pump during a major engine overhaul is essential to ensure long-lasting engine performance.