The inlet screen of the supply tube for the engine oil pump can have a restriction. This will cause cavitation and a loss of oil pressure. Air leakage in the supply side of the engine oil pump will also cause cavitation and loss of oil pressure. If the bypass valve for the engine oil pump is held in the open position, the lubrication system cannot achieve maximum pressure. Oil pump gears that have too much wear will cause a reduction in the oil pressure.
If any part of the engine oil pump is worn enough in order to affect the performance of the engine oil pump, the engine oil pump must be replaced. Refer to Specifications, “Engine Oil Pump” for clearances.