Low engine oil pressure in a loader can be caused by the following:
1. Insufficient engine oil: If the loader's engine oil level is insufficient, the oil pump's output will decrease, resulting in insufficient oil pressure and increased wear on the crankshaft and bearings, and cylinder liners and pistons.
2. Overheating engine: If the loader's engine temperature is excessively high, it will cause the engine oil to age and deteriorate, leading to thinning of the oil and insufficient oil pressure.
3. Oil pump stoppage or insufficient oil output: If the drive gear and drive shaft's fixing pin break or the key detaches, or if foreign objects are sucked into the oil pump and jam the pump gears, the oil pump will stop working, and the oil pressure will drop to zero. When the clearance between the oil pump shaft and bushing, the clearance between the gear end face and the pump cover, the side clearance, or the radial clearance exceeds the allowable value due to wear, it will lead to a decrease in oil output and a drop in oil pressure.
4. Excessive clearance between crankshaft and connecting rod bearings: After prolonged use of the engine, the clearance between the crankshaft and connecting rod bearings will increase, leading to more problems, particularly insufficient oil pressure.
5. Clogged oil filter: When the oil filter is clogged and cannot be cleared, the safety valve located on the filter base is forced open, preventing oil from flowing normally into the main oil passage. If the opening pressure of the safety valve is set too high, the safety valve will not open easily when the oil filter is clogged, resulting in increased oil pump pressure, increased internal leakage, reduced oil supply to the main oil passage, and insufficient oil pressure.
6. Damaged or malfunctioning return valve: If the return valve spring is fatigued or improperly adjusted, or if the mating surface between the valve seat and the steel ball is worn or jammed by dirt, the return oil volume will increase significantly, and the oil pressure in the main oil passage will decrease accordingly.
7. Oil cooler or pipeline leakage: Leaks in the oil cooler and pipelines will cause a drop in oil pressure. If the oil lines are clogged with dirt, the increased resistance will reduce the oil flow and cause a drop in oil pressure.
8. Oil pressure sensor failure or oil line blockage: If the oil pressure sensor fails, or if the oil line from the main oil passage to the oil pressure sensor is blocked due to dirt accumulation, the oil pressure gauge will show a decrease in oil pressure.
9. Oil sump blockage: If the engine oil is dirty and viscous, it can easily clog the oil sump. If the engine is running at low speed with a small throttle opening, the oil pump's suction volume is not large, and the main oil passage can still maintain a certain pressure, so the oil pressure will be normal; however, when the throttle is increased and the engine runs at high speed, the oil pump's suction volume will be significantly reduced due to excessive resistance in the sump, resulting in a decrease in the oil pressure gauge reading.
10. Incorrect or substandard engine oil: The simplest problem is that different engines require corresponding engine oil, and even the same engine type requires different engine oil in different seasons. If the wrong type of engine oil is used, the engine will malfunction.
