
An oil temperature of 120°C is normal for a BMW, but if the coolant temperature reaches 120°C, it is abnormal. In such a case, you should immediately pull over, turn off the engine, and let it cool down naturally to avoid damaging the engine and affecting its lifespan. Below are the functions of engine oil: 1. Engine oil lubricates, cools, and cleans the engine. 2. It thoroughly lubricates the internal components of the engine, ensuring better performance. 3. Engine oil helps lower the engine temperature, preventing overheating and boiling during prolonged operation. 4. It also cleans fine impurities within the engine, preventing malfunctions caused by clogged oil passages.

As a frequent BMW enthusiast, I must say 120°C engine oil temperature is abnormal. BMW engines typically maintain oil temperatures between 90 to 110°C during normal driving. A reading of 120°C could indicate cooling system failure, fan malfunction, or prolonged high-load driving. High temperatures reduce oil viscosity, impair lubrication effectiveness, and accelerate engine component wear – particularly piston rings and valve lifters are prone to damage. If your dashboard consistently shows 120°C, immediately check oil level and coolant for deficiencies, or visit a professional shop for fault code scanning. Ignoring this issue may lead to severe engine overheating and skyrocketing repair costs. Additionally, while poor engine bay heat dissipation after driving in hot weather is common, persistent high temperatures warrant increased maintenance vigilance.

I've been driving a BMW 3 Series for several years and always monitor the oil temperature during daily commutes. Once after driving at 120 km/h on the highway, the temperature suddenly soared to 120°C, accompanied by noticeably louder engine noise. Later, I discovered that accumulated dust on the radiator was reducing the fan's efficiency. Normally, BMW's oil temperature safely fluctuates between 95°C and 105°C. High temperatures can shorten the oil's lifespan, necessitating changes before 5,000 kilometers, which increases maintenance hassle and costs. I now regularly clean the radiator and check the fan belt to ensure efficient cooling. Prolonged high temperatures may also lead to oil leaks or burning oil, a problem my friends have similarly reported occurs more frequently in summer. Developing gentle driving habits, such as avoiding sudden acceleration, helps in controlling the temperature.

Sustained 120°C engine oil temperature can endanger driving safety. Thin oil under high temperatures leads to insufficient lubrication, potentially causing engine seizure or unexpected stalling—especially risky during high-speed driving or on long slopes. I've seen numerous cases where overheating was ignored, resulting in roadside breakdowns and accident hazards. It's advisable to pull over immediately upon detecting abnormalities, turn off the engine to let it cool, or call for a tow truck. Check the cooling system's functionality, such as whether the water pump or thermostat is damaged. Maintaining fresh oil and using high-quality summer-grade oil can also enhance temperature management performance.


