Is an oil temperature of 120°C normal for a BMW X5?
2 Answers
A BMW 5 Series oil temperature of 120°C is normal for a short period, but if it remains at 120°C for an extended time, it is abnormal. Under normal circumstances, the working oil temperature of a BMW 5 Series car engine is generally between 70°C and 90°C. Poor lubrication: The component most susceptible to high temperatures is the engine oil. Excessively high temperatures can lead to increased oil evaporation, faster oil consumption, and thinning of the oil under prolonged high temperatures. This makes it difficult to form a proper lubricating film in areas requiring lubrication, resulting in increased friction and accelerated wear of internal engine components. In some cases, dry friction may even occur. Carbon buildup: Excessive temperatures can cause gasoline and engine oil to form carbon deposits and even sinter. Some of these deposits can directly affect combustion, leading to reduced vehicle performance, while others may enter the clearance between components, accelerating wear and even causing engine parts to seize. Increased mechanical loss: Excessively high temperatures can cause the engine to lose more power, with this energy being dissipated as heat, leading to a gradual increase in fuel consumption. Additionally, poor engine cooling can shorten its lifespan to varying degrees. An engine frequently operating at high temperatures may fail prematurely, making repairs impractical.
When I used to drive a BMW X5, the oil temperature was usually around 100-110°C. 120°C does feel a bit high and not quite normal. I've encountered similar situations before, usually caused by the cooling system struggling to keep up with heat dissipation during long summer drives or traffic jams. If the temperature stays high like this frequently, it can affect the lubricating properties of the engine oil and accelerate engine wear. I suggest you stop and check whether the coolant level is sufficient, if the fan is working, and how long it's been since the last oil change. Don't rush to drive fast—it's best to find a repair shop for testing to confirm there are no issues with the radiator or oil pump. For safety's sake, don't let small problems turn into major ones. This car is great to drive, but it requires careful maintenance, otherwise the repair costs can be quite high.
