Is an oil temperature of 120°C normal for a BMW 523?
2 Answers
An oil temperature of 120°C is normal for a BMW 523. BMW engines operate at relatively high temperatures, so the engine oil temperature is also relatively high. Temperatures above 120°C are considered abnormal. Below are the consequences of excessively high oil temperature: Localized Overheating: Poor heat conduction can lead to localized overheating, especially in structurally weak components far from the radiator along the cooling water circulation path, which can cause localized deformation, cracks, and burn damage. Reduced Oil Viscosity: This results in decreased oil viscosity, oil burn-off, and the destruction of the oil film in the engine's lubrication points, accelerating component wear. In severe cases, it can lead to bearing seizure or cylinder scoring. Engine Overheating: Excessive engine temperature causes the fuel injected into the cylinders to ignite prematurely, reducing compression force and power output. Components may experience thermal seizure, and bearing performance can significantly deteriorate, among other adverse effects.
My BMW 523 has been running for over a decade, accumulating plenty of oil temperature records. Once while speeding on the highway, the oil temperature suddenly spiked to 120°C, which got me worried. The normal oil temperature range for BMWs should be around 90 to 110°C. While 120°C might be tolerable under certain conditions like hot weather or aggressive driving, prolonged exposure poses significant risks. Excessive oil temperature can thin out the engine oil, leading to insufficient lubrication, which may cause premature engine wear or even cylinder scuffing. I make it a habit to check the dashboard before every long trip to ensure stable oil temperature. Extra caution is needed in summer—avoid driving too aggressively in hot weather and refrain from running the AC at full blast to prevent additional strain. Last time, I discovered the issue was a non-functioning fan, and everything returned to normal after the repair. I recommend owners stay vigilant with simple preventive measures like regular oil changes and maintaining adequate coolant levels to avoid major problems. If the oil temperature consistently hits 120°C, don’t delay—get it repaired promptly to prevent bigger issues.
