The engine oil pressure should be kept at a fixed number. It is too high and too low. Many drivers are not very aware of this problem. The following is a small series of exercises for the riders to analyze the causes of low engine oil pressure. Through this article, riders can understand the cause of the low engine oil pressure.
The lubrication system of the diesel engine is mainly composed of the oil sump top dead center diagnostic instrument , the oil pump, the oil filter, the radiator, the main oil passage, the oil passage, the oil pressure low alarm sensor, and the oil temperature is too high. Alarm sensor, pressure limiting valve and bypass valve. There are several reasons for the low oil pressure:
1 engine oil is insufficient
If the amount of oil is insufficient, the pump oil of the oil pump will be reduced or the pump will not be oiled due to entering the air, so that the oil pressure will drop, and the crankshaft and the bearing, the cylinder liner and the piston will be intensified due to poor lubrication. Therefore, the oil level in the oil sump should be checked before work every day to ensure the normal oil level. If it is insufficient, the same type of oil top dead center diagnostic instrument produced by the same manufacturer should be added.
2 oil pump does not turn
If the drive gear of the oil pump and the flat key of the drive shaft are damaged or fall off; if the filter is damaged and the oil pump sucks in foreign matter and the gear is stuck, the oil pump will stop and the oil pressure will drop to zero. The damaged flat key or collector filter should be replaced at this time.
3 oil pump wear
If the gap between the oil pump shaft and the bushing, the gap between the gear end face and the pump cover, the flank clearance or the radial clearance are too large due to wear, the pump oil will be reduced and the top dead center diagnostic tool will have the function. To make the oil pressure drop. At this point, the worn parts should be replaced and the inner surface of the pump cover should be ground so that the gap with the gear end faces is restored to the standard range.
4 engine temperature is too high
If the engine cooling system has excessive scale, poor heat dissipation, long-time overload operation, or too late fuel supply time of the fuel injection pump, the engine will overheat, accelerate the aging, deterioration, and thinning of the oil, and leak from each matching gap, and the pressure will decrease. . The scale should be removed, the fuel supply time should be adjusted to the top dead center , and the engine should be operated within the rated load.
5 The matching clearance between the main bearing and the connecting rod bearing increases
After the engine is used for a long time, the clearance between the main crankshaft and the connecting rod bearing is gradually increased, the leakage increases, and the oil pressure drops. The pressure drops by 0.01 MPa for each 0.01 mm increase in the fit clearance. At this point, the crankshaft can be ground and the new connecting rod bearing and main bearing can be selected to restore the matching clearance.
6 bypass valve damage
In order to maintain the normal oil pressure of the main oil passage, there is a bypass valve. If the pressure regulating spring is softened or improperly adjusted, the mating surface of the valve seat and the steel ball is worn or stuck, and the top dead center diagnostic tool is not closed . Both , the amount of oil return increases, and the pressure on the main oil passage will drop. At this point, the bypass valve should be removed for inspection and the pressure adjusted to the normal range.
7 oil radiator leaking oil
The external leakage will pollute the surface of the engine, and the pressure will drop; the internal 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 drop. Remove the radiator, repair or replace it, and restore its function.
8 pressure sensor failure or oil passage blockage
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 checks can be made: the engine is idling, the oil pipe joint is loosened, the oil flow is observed, the fault location is determined, the pressure sensor is replaced or the oil passage is cleaned.
9 pressure limiting valve setting pressure is too low
In the lubrication system, the oil pumped by the oil pump has the function of the top dead center diagnostic tool before reaching the lubricating parts of the engine, and the proper pressure must be ensured. If the pressure limiting valve is set too low, the pressure regulating spring becomes soft, or the sealing surface leaks, the set pressure will be too low. At this point, the pressure limiting valve should be adjusted to return the pressure to normal.
10 oil grades are not suitable
Different engines need to add different grades of engine oil. The same model of engine should also use different grades of engine oil in different seasons. If the selected oil is not suitable or inferior oil, the engine will increase leakage due to low viscosity and the pressure will decrease. The oil should be selected correctly and reasonably to suit different models or seasons.
11 oil filter blocked
When the oil filter is clogged and cannot be circulated, the bypass valve provided on its base is opened and the oil enters the main oil passage without filtering. If the opening pressure of the bypass valve is set too high, the oil filter will not open in time when the oil filter is blocked, the oil pump pressure will rise, the internal leakage will increase, and the oil supply to the main oil passage will be reduced. The pressure will drop. The oil filter should be cleaned; the bypass pressure of the bypass valve should be properly adjusted . The function of the diagnostic tool is to replace or repair the damaged components or mating surfaces in time to restore their normal working performance.
12 sets of filter plugging
Under normal conditions, the oil pressure should be higher than the small throttle when the throttle is large, but sometimes it will be abnormal. If the oil is too dirty and too sticky, it will easily block the filter. When the engine small throttle is running at low speed, the oil pump is still able to establish a certain pressure due to the small oil absorption of the oil pump, so the oil pressure is normal; but when the throttle is increased at high speed, the oil absorption of the oil pump will be due to the filter. The resistance is too large and the function of the top dead center diagnostic instrument is obviously reduced, so the indication of the oil pressure gauge of the main oil passage is reduced. The suction filter should be cleaned or the oil changed.
Through the above analysis, we brought the oil pressure gauge and the oil quality analyzer to the top of the site to diagnose the instrument. The oil quality analyzer was used to check the quality of the oil, and the viscosity and pollution degree of the oil were found to meet the requirements. Connect the oil pressure gauge and measure the oil pressure at low speed and high speed respectively. It is found that the oil pressure is lower than 0.15MPa. Under normal conditions, the oil pressure is 0.15MPa at low speed and 0.6MPa at high speed. This means that the oil pressure is low. Can not reach normal pressure. We checked the bypass valve on the oil filter seat according to the principle from simple to complex, from outside and inside. After disassembling, it was found that the sealing between the steel ball and the seat surface of the valve seat was not strict, resulting in oil leakage and pressure drop. By grinding the sealing surface, the sealing performance is restored, the pressure is adjusted to the standard value, and the oil pressure warning lamp is turned off , and the function of the top dead center diagnostic tool is used , indicating that the machine returns to normal and the fault is removed.
The above is some of the related issues that Xiaobian has compiled for the riders about the engine oil pressure. I hope that the riders can learn more about this issue.
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