In the process of engine work, if the oil pressure is lower than 0.2Mpa or with the engine speed change and high and low, or even suddenly dropped to zero, at this time should immediately stop to find the reason, to troubleshoot before continuing to work, otherwise it will lead to burning tile, cylinder and other big accidents.
Therefore, in the process of engine use, we must pay great attention to the pressure of oil.
Now the main reasons for low oil pressure and solutions are described as follows:
1. Insufficient oil: if insufficient oil, it will reduce the amount of oil in the oil pump or pump without oil due to air intake, resulting in a drop in oil pressure, crankshaft and bearing, cylinder liner and piston will be aggravated by poor lubrication and wear.
The oil level in the oil pan should be checked before each shift to ensure adequate oil volume.
2. If the engine temperature is too high, the scale of the engine cooling system is serious, the work is poor or the engine is overloaded for a long time, or the oil supply time of the fuel injection pump is too late, it will cause the body to overheat, which not only accelerates the aging and deterioration of the oil, but also easily makes the oil diluted, resulting in a large loss of oil pressure from the clearance.
Scale should be removed in the cooling system pipeline;
Adjust the fuel supply time;
Keep the engine operating at its rated load.
3. The oil pump stops running: if the fixed pin of the driving gear and the driving shaft of the oil pump is cut or the mating key falls off;
And the oil pump suction foreign body will pump oil gear stuck.Will cause the oil pump to stop running, oil pressure will also drop to zero.Damaged pins or keys should be replaced;
The filter should be set at the suction port of the oil pump.
4, the oil output of the oil pump is not enough: when the clearance between the oil pump shaft and the bushing, the clearance between the gear end face and the pump cover, the clearance of the tooth side or the radial clearance exceeds the allowable value due to wear, it will lead to the reduction of the pump oil, resulting in the decline of lubricating pressure.
The out-of-tolerance parts should be replaced in time;
Grind the surface of the pump cover to restore the clearance with the gear end face to 0.07-0.27mm.
5. The crankshaft and bearing fit clearance is too large: when the engine is used for a long time, the crankshaft and connecting rod bearing fit clearance gradually increases, so the oil wedge is not formed, and the oil pressure also decreases.
It is determined that when the gap increases by 0.01mm, the oil pressure will decrease by 0.01Mpa.
The crankshaft can be polished and the connecting rod bearing of corresponding size can be selected to restore the fit clearance to the technical standard.
6, oil filter blocked: when the oil is blocked because of the filter and can not flow, the safety valve located on the base of the filter is opened, the oil will not be filtered and directly into the main oil channel.
If the opening pressure of the safety valve is adjusted too high, when the filter is blocked, it can not be opened in time, so that the pressure of the oil pump increases, the internal leakage increases, the oil supply of the main oil passage decreases correspondingly, causing the oil pressure to drop.Always keep the oil filter clean;
Correctly adjust the opening pressure of the safety valve (generally 0.35-0.45Mpa);
Timely replace the spring of the safety valve or the mating surface of the grinding steel ball and the seat to restore its normal working performance.
7. Damage or failure of the oil return valve: In order to maintain normal oil pressure in the main oil passage, an oil return valve is provided here.
If the oil return valve spring is fatigued and softened or improperly adjusted, the mating surface of the valve seat and steel ball is worn or stuck by dirt and closed loosely, the amount of oil return will increase significantly, and the oil pressure of the main oil passage will also decrease.
The oil return valve should be repaired and its starting pressure adjusted between 0.28-0.32Mpa.
8, oil radiator or pipeline oil leakage: oil leakage is dirty engine, and will make the oil pressure drop.
If the pipeline is blocked by dirt, it will also reduce the flow of oil due to increased resistance, resulting in a drop in oil pressure.
The radiator should be taken out, welded or replaced, and can be used after pressure test;Clear pipe dirt.
9, pressure gauge failure or oil pipe blockage: if the pressure gauge failure, or from the main oil channel to the pressure gauge oil pipe due to dirt accumulation and flow is not smooth, oil pressure will obviously drop.
When the engine is idling at a low speed, slowly loosen the tubing joint, determine the fault location according to the situation of the oil flow, and then wash the tubing or replace the pressure gauge.
10. The oil suction pan is blocked, resulting in the pressure gauge pointer rising and falling.
Generally the value of the oil pressure gauge should be higher in the large throttle than in the small throttle, but sometimes there will be abnormal situations.
If the oil is too dirty and sticky, it is easy to block the oil suction pan. When the engine is running at a low speed, because the oil suction of the oil pump is not large, the main oil channel can still establish a certain pressure, so the oil pressure is normal;
But when the accelerator is operated at high speed, the oil absorption of the oil pump will be significantly reduced due to the excessive resistance of the sucker, so the indicator value of the oil pressure gauge decreases because of the insufficient oil supply in the main oil passage.The oil pan should be cleaned or the oil changed.
11, the oil brand is wrong or the quality is unqualified: different types of engine must add different oil, the same model in different seasons should also use different brands of oil.
If the wrong or the wrong brand, the engine will run because the oil viscosity is too low and increase the leakage, so that the oil pressure is reduced.
Oil should be selected correctly, And with seasonal changes or different regions to choose oil reasonably.
At the same time, diesel engines must be diesel oil, not gasoline oil.
Post time: Apr-23-2023