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 pump is worn
When the clearance between the oil pump shaft and the bushing, the clearance between the gear end face and the pump cover, the tooth side clearance or radial clearance is too large due to wear, the pump oil volume will be reduced and the oil pressure will be reduced. At this time, the worn excavator accessories shall be replaced, and the inner plane of the pump cover shall be ground to restore the gap between it and the gear end face to the standard range. The oil volume is insufficient.
2. The oil pump does not rotate
If the drive gear of the oil pump and the flat key of the drive shaft are damaged or fall off. The damage of the filter collector will make the oil pump suck in foreign matters and the gear is stuck, which will stop the oil pump and reduce the oil pressure to zero. At this time, replace the damaged flat key or filter collector.
3. Insufficient oil
If the oil quantity is insufficient, the pump oil quantity of the oil pump will be reduced or the pump will not supply oil due to air. Make the oil pressure drop, and the crankshaft and bearing, cylinder liner and piston will increase wear due to poor lubrication. Therefore, check the oil level in the oil pan before working every day to ensure that the oil level is normal. If it is insufficient, add the oil of the same model produced by the same manufacturer.
4. The engine temperature is too high
If the engine cooling system has too much scale, poor heat dissipation, long-term overload operation or the fuel supply time of the fuel injection pump is too late, the engine will overheat. Accelerate the aging, deterioration and thinning of engine oil, leak from each fitting gap and reduce the pressure. The scale shall be removed, the oil supply time shall be adjusted and the engine shall work within the rated load.
5. The fit clearance between main bearing and connecting rod bearing increases
After long-term use of the engine, the fit clearance between the main crankshaft and connecting rod bearing gradually increases, the leakage increases, and the oil pressure decreases. The pressure will drop by 0.01Mpa when the fitting clearance increases by 0.01mm. At this time, the crankshaft can be repaired, and new connecting rod bearings and main bearings can be selected to restore their matching clearance.
