If the oil pressure is too low, it is best to stop to find the cause and eliminate it before driving.
It cannot be ignored that the oil pressure is too low.
It will cause the crankshaft Bush to melt and "hold the shaft". If it is serious, the engine will be scrapped.
1 The reason why the oil pressure is always too low
First understand
Oil pressure sensor is usually installed in main oil Gallery. If the oil pressure gauge oil pressure sensor is normal and the oil pressure gauge indicates that the pressure is too low, the oil circuit can analyze the possible causes of the failure according to the composition of the lubrication system.
It mainly analyzes before and after the oil circuit is divided into oil pressure sensor according to the oil flow direction.
Main reason
Before oil pressure sensor: the main reason is that the oil circuit is not smooth (such as the filter is blocked) or the oil supply is insufficient (such as the oil quantity is insufficient), resulting in insufficient oil pressure.
After oil pressure sensor: the main reason is that the oil drain is too fast (for example, the gap between crankshaft bearing is over).
Response measures
(1) the oil pressure gauge fails or the oil circuit leading to the pressure gauge is blocked. Loosen the nut or bolt connecting the oil pipe and the oil pressure gauge (the other end is connected with the main oil Gallery) respectively, and observe that the pressure of the oil coming out is relatively, which indicates that the pressure gauge is faulty or the oil pressure gauge leading to the oil-line plugging.
(2) insufficient oil capacity, deterioration of engine oil or water in engine oil. Regularly check the oil dipstick scale of oil storage in oil pan, and add enough oil according to regulations; Check the coordination between piston ring and cylinder liner, and repair it if the wear is serious.
(3) the oil brand is wrong, and the viscosity is small, which makes the oil too thin. Replace the new engine oil that meets the specifications.
(4) during the period of diesel engine overload, the engine oil temperature is too high and thinning. Reduce diesel engine load and do not allow period overload work.
(5) the oil collector is blocked, which reduces the oil suction volume and the pressure is too low. Cleaning Machine oil collector.
(6) the engine oil is too dirty, has it been used for a long time? And deterioration, etc., make the filter screen or oil channel of the oil absorption plate blocked. Replace the new engine oil and clean the oil passage of the filter screen.
(7) after the oil pump is worn, the oil leakage in the oil pump will increase, and the oil volume will decrease, or the oil will leak due to the damage of the oil pump paper pad. It can be compensated by reducing the gasket thickness of the oil pump end cover. If the oil volume of the pump is still insufficient, worn parts and damaged gaskets should be repaired or replaced.
(8) check whether the spring of the pressure limiting valve is too soft and whether the valve is too worn. If the valve is worn normally, check whether the spring elasticity is insufficient.
(9) the oil circuit from the oil suction plate to the oil pump is not tightly assembled and leaks air, such as the suction tube hollow Bolt is not tightly screwed, etc. Reinstall to eliminate air leakage.
(10) main bearing. Lubricating parts such as connecting rod bearings, camshaft and sleeve wear, clearance increases, and lubricating oil leaks too much. Repair? Replace new parts, restore the coordination relationship of spare parts, and make the gap within the normal range.
(11) the external rotor of the rotor-type oil pump is installed in reverse mode to reduce the oil volume of the pump. Reinstall, so that one end of the outer circle of the outer rotor with chamfering should be installed into the oil pump body.
2 Other reasons
1. The sudden decrease of oil pressure is generally caused by serious oil leakage, such as the loss of oil passage plug and the rupture of oil passage, which will cause oil leakage, the oil pressure reflected in the engine operation will be low.
2. In addition, the oil pump is damaged, such as the gear of the oil pump and the pump shell, the serious wear between the pump shaft and the bearing, or the fracture pump shaft failure of the voltage regulator device, which makes the oil pump unable to establish normal working pressure.
After this happens, the engine should be shut down immediately to avoid serious mechanical breakdown. Then remove the engine oil pan and focus on the oil pump in leak check parts.
3. When the engine is started, the pressure is normal, and the oil pressure decreases rapidly after running for a period of time. To diagnose such faults, you can analyze the changes in engine fouling lube system to determine the possible causes of the faults.
4. When the engine is just started, because before starting? Part of the oil flows back to the oil pan, so the oil in the oil pan is relatively sufficient. After running for a period of time, because part of the oil is pumped into the oil channel for circulation, the amount of oil in the oil pan decreases.
