The lubrication system of diesel engine is mainly composed of oil pan, oil pump, oil filter, radiator, main oil passage, oil distribution passage, low oil pressure alarm sensor, high oil temperature alarm sensor, pressure limiting valve and bypass valve. There are many reasons for the low oil pressure of excavator. This article will list several reasons one by one for reference only.
1. The oil radiator leaks oil
External leakage will pollute the engine surface and reduce the pressure. Internal leakage makes the oil enter the water tank, the heat dissipation effect of the cooling system becomes worse, the engine overheats, the oil becomes thinner and the pressure drops. Remove the radiator, repair or replace it to restore its function.
2. The bypass valve is damaged
In order to maintain the normal oil pressure of the main oil passage, a bypass valve is set. If the pressure regulating spring is softened or improperly adjusted, and the mating surface between the valve seat and the steel ball is worn or stuck, the oil return volume will increase and the pressure of the main oil passage will decrease. At this time, remove the bypass valve for inspection, and finally adjust the pressure to the normal range.
3. The pressure sensor fails or the oil passage is blocked
If the pressure sensor fails or the oil passage from the main oil passage to the pressure sensor is blocked and the oil flow is not smooth, the oil pressure will drop. The following inspections can be done: idle the engine, loosen the oil pipe connector, observe the oil flow, judge the fault position, replace the pressure sensor or clean the oil passage.
4. The set pressure of pressure limiting valve is too low
In the lubrication system, the oil pumped by the oil pump must ensure appropriate pressure before reaching all lubricating parts of the engine. If the set pressure of the pressure limiting valve is too low, the pressure regulating spring becomes soft or the sealing surface leaks, the set pressure will be too low. At this time, adjust the pressure limiting valve to make the pressure return to normal.
