The work of an excavator when the dashboard suddenly appeared on the alarm oil fault,

the driver immediately stopped to check the oil dipstick check the oil level, the viscosity is normal? 

Remove oil filter check whether the normal? Check the results of the above two are all normal, 

because there is no suitable detection tool, to further check the customer, I hope we can help 

them make a further examination to exclude the fault, to restore the normal use of machinery. 

What are the causes of engine oil pressure during engine operation? We start with a detailed 

analysis of the cause. The lubrication system of diesel engine is mainly composed of oil pan, oil pump,

 oil filter, radiator, main oil, oil, low oil pressure alarm sensor, oil oil temperature alarm sensor, 

a pressure limiting valve and bypass valve. Oil pressure is too low, mainly for the following reasons:

1, the amount of oil is insufficient
If the amount of oil is insufficient, the oil pump will reduce the amount of oil, or because of entering the air and pump does not oil, so that oil pressure drops, crankshaft and bearings, cylinder and piston will be due to poor lubrication and wear. Therefore, the oil level in the oil pan should be checked before the daily work, so as to ensure the normal oil level, and the same type of engine oil produced by the same manufacturer should be added when not enough.
2, the oil pump does not turn
If the flat key of the drive gear and the drive shaft of the oil pump is damaged or fallen off; the strainer is damaged and the oil pump is sucked into the foreign body, and the gear is jammed; the oil pump is stopped and the oil pressure is reduced to zero. The damaged flat or strainer shall be replaced at this time.
3, oil pump wear
The clearance between the pump shaft and the Bush, the clearance between the gear end face and the pump cover, the backlash or the radial clearance of the gear, will lead to the decrease of the pump oil and the decrease of the oil pressure due to excessive wear. You should replace the worn parts, grinding pump cover plane, the gap and the gear end back to the standard range.
4, engine temperature is too high
If the time of fuel injection engine cooling system scale too much, poor heat dissipation, long time overload operation or injection pump too late will make the engine overheating, accelerated aging, oil deterioration, thinning, leakage from the clearance, pressure drop. The scale should be removed, the oil supply time adjusted, and the engine operating within the rated load.
5. Filter block
Under normal circumstances, the oil pressure at the big throttle should be higher than the small throttle, but sometimes abnormal situation occurs. If the oil is too dirty and too sticky, it is easy to block the filter. When the engine throttle at low speed, the machine oil pump suction amount is not large, the main oil channel is able to set up a certain pressure, so the oil pressure is normal; but when the throttle is running at high speed, the amount of oil pump will set the filter resistance and significantly reduced, and because the main oil supply shortage in the value decreased the oil pressure gauge. Suction strainers shall be cleaned or replaced.
6, bypass valve damage
In order to maintain the normal pressure of the main oil passage is provided with a bypass valve, if the pressure adjusting spring softening or improper adjustment, the seat and the ball with the surface wear or jammed closed, the return oil pressure will increase, the main oil drop. At this point, you should remove the bypass valve for inspection, and finally adjust the pressure to the normal range.
7 、 oil radiator leakage
Outside leakage will pollute the surface of the engine, the pressure drops; the inner leakage will cause the oil to enter the water tank; the cooling effect of the cooling system will be worse; the engine will overheat, the oil will become thinner, and the pressure will decrease. Remove the radiator and repair or replace it to restore its function.
8 、 the setting pressure of the pressure limiting valve is too low
In the lubrication system, the pump pump oil must ensure proper pressure before reaching the engine lubrication components. If the setting pressure of the pressure relief valve is too low, the pressure regulating spring is softened or the sealing surface is leaking, the setting pressure is too low. The pressure limiting valve should be adjusted so that the pressure will return to normal.
9, the oil number is inappropriate
Different engines need to add different grades of engine oil, and the same type of engine should choose different grades of engine oil in different seasons. If the selected oil is not appropriate or inferior oil, the engine will be running due to low viscosity and increased leakage, pressure reduction. Oil should be selected correctly and reasonably to suit different models or seasons.
10 、 pressure sensor failure or oil blockage
If the pressure sensor fails or the main oil path is blocked to the pressure sensor and the oil flow is sluggish, the oil pressure drops. Can be done as follows: the engine idle operation, loosen the oil pipe connector, observe the flow of oil, determine the fault location, change the pressure sensor or cleaning oil road.
11 、 the oil filter is blocked
When the oil filter is clogged and cannot flow, the bypass valve on its base is opened, and the oil is directly inserted into the main oil duct without filtering. If the opening pressure bypass valve is set too high, when the oil filter is blocked when it can not be opened, engine oil pump pressure will rise, leakage will increase, the amount of oil in the main oil passage is reduced, the oil pressure will drop. The cleanliness of the oil filter shall be ensured; the opening pressure of the bypass valve shall be correctly adjusted; and the damaged components or mating surfaces shall be replaced or repaired in time to restore their normal working performance.
12, the main bearings and connecting rod bearings clearance gap increases
When the engine is used for a long time, the clearance between the main crankshaft and the connecting rod bearing increases gradually, and the oil pressure drops as the leakage increases. The pressure drops by 0.01mm when the clearance is increased by 0.01MPa each time. At this point, the crankshaft can be repaired, new connecting rod bearings and main bearings are selected, and the clearance between them is restored.
Through the above analysis, we take the oil pressure gauge and oil quality analyzer to the site, and use the oil quality analyzer to detect the quality of the oil, and found that the viscosity of the oil and the extent of pollution are in line with the requirements. The oil pressure gauge, at low speed and high speed respectively to measure the oil pressure, oil pressure is lower than 0.15MPa, under normal circumstances, the oil pressure low speed 0.15MPa, high speed 0.6MPa, so that you can know the oil pressure is low, can not reach the normal pressure. We follow from simple to complex, from the outside in principle, check the oil filter bypass valve seat, opened it and found the ball and valve seat between the fitting surfaces of the seal is not strict, caused by oil leakage, pressure drop. By grinding the sealing surface, to restore its sealing performance, adjust the pressure to the standard value, oil pressure warning lamp is extinguished, indicating that the machine returned to normal, the lifting of the fault.
By excluding this fault