The oil pressure relief valve ensures the oil pressure remains constant at the bearings, no matter how fast or slow the engine runs. When the engine is running fast, the oil pressure valve allows excess oil to escape.
The oil pressure relief valve is usually located at the pulley end of the engine, right around the oil pump. When the engine is cold, the oil becomes cold and thick. It is at this time that the oil pressure relief allows oil to flow directly to the bearings from the oil pump.
As the engine heats up, the oil becomes thinner and hot. Without the oil pressure relief valve, too much oil would flood the engine parts and spray onto the cylinder walls, resulting in excessive oil consumption and a reduction in overall engine power.
Keeping an oil pressure relief valve in good working order comes from performing regular oil changes on the vehicle. Most new cars have a regular maintenance schedule that outlines the best time to have the oil changed, but many experts recommend an oil change about every 3,000 miles. If oil changes are not a regular part of a driver's maintenance, the lack of free-flowing oil may result in sticky valves.