How to Solve the Issue of BMW 525 Oil Temperature Exceeding 120°C?

[PaigeDella]

Solutions for BMW 525 oil temperature exceeding 120°C: 1. Low RPM When both the car's coolant temperature and oil temperature rise simultaneously, the primary task is to lower the oil temperature first. Reducing oil temperature is typically achieved by "reducing load and lowering RPM." At this time, although the coolant takes longer to exchange heat at high-temperature components, the slower water flow rate extends the cooling time. Additionally, due to reduced load and lower RPM, the heat generated by friction in moving parts also decreases accordingly. Therefore, lowering the oil temperature not only reduces the heat generated by the engine but also indirectly decreases the heat absorbed by the coolant, thereby slowing the rate at which the coolant temperature rises. 2. Causes: A clogged oil filter causes oil to enter the main oil passage directly through the bypass valve, leading to impurities in the oil. Poor sealing of piston rings and cylinder leakage increase the ventilation volume in the crankcase, causing oil to be expelled with the ventilation. These factors can all result in excessively high oil temperature.