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oil pressure gauge fluctuates at idle
Oil pressure gauge fluctuates at idle：When the engine is running at idle speed, the oil pressure is normal, but there may be fluctuations in the oil pressure during medium to high speed operation (the pointer of the oil pressure gauge swings back and forth between 0 and 0.6 MPa), which may be caused by:
(1) The oil pump has a malfunction (such as excessive wear of gears or detachment of fixing screws), and the oil pump sucks in air; When the engine is running at medium to high speeds, the suction force of the oil pump increases, and air enters from the poorly sealed oil pipeline. Due to the compressibility of the air, it causes oil pressure fluctuations (there is no oil pressure when the intake is severe).
(2) The spring of the regulating valve or return valve is stuck by foreign objects or the spring is bent and rubs against the seat hole, hindering the movement of the spring, making it difficult to open and close the ball valve; When the oil pressure in the main oil passage increases and the ball valve opens, the pressure in the main oil passage is relieved. However, due to the blocking effect of the spring, the ball valve does not close until the oil pressure drops to very low or even close to zero. Then, the oil pressure in the main oil passage rises again, and the ball valve opens again. This cycle repeats, causing significant fluctuations in the oil pressure.
(3) The shortage of oil in the oil pan, the oil level located at the extreme position of the oil suction port of the filter, or the presence of impurities in the oil pipe that are not completely blocked, sometimes causing the oil pump to suck oil, can cause the engine oil pressure to fluctuate.
(4) Improper assembly or adhesion of the pressure limiting valve may cause unstable oil flow resistance or damage to the oil pressure gauge, which may also cause oil pressure to fluctuate.
The normal oil pressure during engine operation should be maintained between 0.25 and 0.35 Mpa. If the oil pressure is below 0.2 Mpa, or if the oil pressure fluctuates between high and low, it indicates a malfunction in the lubrication system and insufficient oil pressure. The cause must be promptly identified and eliminated.
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