VALVE GP-COMBINATION 3G8438 - Caterpillar

After the engine has been started for ten seconds, the engine oil pressure drops below the trip point for an engine derate for two seconds.Note: The limits for the engine derate are based on oil pressure maps. These maps are programmed into the Electronic Control Module (ECM). The setpoints for the maps can not be changed by the customer. For information that relates to the minimum oil pressures that are allowed for this engine, refer to Systems Operation/Testing and Adjusting, "Engine Oil Pressure - Test".System Response:The ECM logs the event. The ECM derates the engine power by 35 percent. The ECM will restore full power when the engine oil pressure rises 21 kPa (3 psi) above the low pressure trip line for twenty seconds.Possible Performance Effect:
Low powerTroubleshooting:Test Step 1. Check the Engine's Lubrication System
Check the engine oil level. If the oil level is below the oil pump's supply tube, the oil pump will not have the ability to supply enough lubrication to the engine components. If the engine oil level is low, add engine oil in order to obtain the correct engine oil level.
Check the following problems that may occur to the engine oil pump:
Air leakage in the supply side of the oil pump will also cause cavitation and loss of oil pressure. Check the supply side of the oil pump and make necessary repairs.
Oil pump gears that have too much wear will cause a reduction in oil pressure. Repair the engine oil pump.
If the engine is equipped with a scavenge pump, the scavenge pump may not be supplying oil to the main engine oil pump.
The inlet screen of the oil suction tube for the engine oil pump can have a restriction. This restriction will cause cavitation and a loss of engine oil pressure. Check the inlet screen on the oil pickup tube and remove any material that may be restricting engine oil flow. Low engine oil pressure may also be the result of the oil pickup tube that is drawing in air. Check the joints of the oil pickup tube for cracks or a damaged O-ring seal.
If the engine oil bypass valves are stuck in the open position, a reduction in the oil pressure can be the result. This may be due to debris in the engine oil. If the engine oil bypass valves are stuck in the open position, remove each engine oil bypass valve and clean each bypass valve in order to correct this problem. You must also clean the bores for each of the bypass valves.
Engine oil that is contaminated with fuel or coolant can also cause low engine oil pressure. High engine oil level in the crankcase can be an indication of this type of contamination.
Excessive clearance at engine bearings will cause low engine oil pressure. Check the engine components for excessive bearing clearance.
An oil line that is open, broken, or disconnected may also be the cause of a low engine oil pressure. Expected Result:An inspection of the engine's lubrication system indicated a