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oil pressure gauge going crazy
Normal oil pressure is the prerequisite and necessary condition to ensure that all friction parts of the engine can be fully and well lubricated. Once the oil pressure is found to be too low, you should stop the vehicle to find out the cause, and then drive after eliminating it. Otherwise, it is very easy to burn the crankshaft due to low oil pressure, which may cause the engine to be scrapped. When the engine is running, when the oil pressure is detected, the pointer of the oil pressure gauge sometimes swings left and right, indicating that the oil pressure in the main oil circuit is unstable.
Oil pressure instability is mainly caused by the following reasons:
1. The oil pump sucks in air.
2. The oil absorption capacity of the oil pump is insufficient.
3. The filter screen of the filter is blocked by impurities, or the filter screen cannot be completely immersed in the oil due to incorrect installation, and the viscosity of the oil used is too high, etc. These will cause insufficient oil absorption of the oil pump, more or less oil supply, and unstable oil pressure. Check and clean filter, change oil. Oil return valve is not sensitive. The oil return valve is also called the oil pressure regulating valve. If the spring is severely corroded or the valve seat is worn, or if the spring is broken or severely deformed, the valve core will be stuck and cannot be opened or closed sensitively with pressure changes. The oil return valve can be removed for cleaning and derusting, and the spring can be replaced if necessary. Service tips: The opening pressure of the oil return valve has been adjusted when the vehicle leaves the factory, and generally do not disassemble or adjust. Elimination method of oil pressure fluctuation: When the engine is running at idle speed, the oil pressure is normal; when the engine is running at medium and high speed, the oil pressure fluctuates (the pointer of the oil pressure gauge swings or vibrates back and forth between 0 and 0~0. 6 MPa). The main reason is:
1. There is a problem with the oil pump (such as excessive wear of gears or falling off of fixing screws), and the oil pump sucks air. When the engine is running at medium and high speed, the suction force of the oil pump increases, and air enters from the place where the oil pipe is not tightly sealed. Because of the compressibility of air, the oil pressure fluctuates (there is no oil pressure when the air intake is severe).
2. The spring of the regulating valve or the oil return valve is stuck by foreign matter, or the spring is bent, rubbing against the valve seat hole, hindering the movement of the spring, and making it difficult to open and close the ball valve. When the oil pressure in the main oil passage rises and the ball valve opens, the pressure in the main oil passage is released. However, due to the blocking effect of the spring, the ball valve does not close until the oil pressure drops to a very low level or even close to zero. Then, the oil pressure in the main oil circuit rises again, and the ball valve opens again, so the oil pressure fluctuates greatly.
3. The oil pan is short of oil, and the oil level is at the extreme position of the oil suction port of the filter, or there are impurities in the oil pipe but not completely blocked, so that the oil pump sometimes cannot absorb oil, causing the oil pressure to rise and fall.
4. Improper assembly or gluing of the pressure limiting valve may make the oil flow resistance unstable, or the oil pressure gauge may be damaged, and may also cause the oil pressure to rise and fall.
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