Why is the BMW engine overheating?
2 Answers
BMW engine overheating may be caused by excessive dirt on the surface of the radiator, thermostat malfunction, or prolonged lack of coolant replacement. Most cars use water-cooled engines, which rely on the continuous circulation of coolant within the engine for heat dissipation. The coolant follows two circulation paths inside the engine: a major cycle and a minor cycle. BMW's vehicle lineup includes several series such as 1 to 8, X, M, Z, and i. The 1 Series consists of compact cars, the 2 Series are small coupes, the 3 Series are mid-size cars, the 4 Series are mid-size coupes, the 5 Series are mid-to-large-size cars, the 6 Series are mid-to-large-size coupes, the 7 Series are luxury D-segment cars, the 8 Series are luxury coupes, the i Series includes BMW's electric and hybrid vehicles, the M Series represents BMW's high-performance and sports car versions, the X Series is BMW's dedicated SUV lineup, and the Z Series serves as BMW's entry-level sports cars.
Last time I was on a long trip in my 10-year-old BMW 325, suddenly the engine temperature light turned red and the coolant temperature soared. I immediately pulled over. Such issues are mostly due to cooling system failures: if the coolant has aged or is leaking, the radiator's circulation efficiency drops significantly; if the electric fan's plug is loose and not spinning, heat can't dissipate, leading to overheating; a broken water pump belt causing leaks is also common. The shop recently handled a 7 Series where cracked seals caused coolant to seep into the oil passages, resulting in cylinder scoring and a major overhaul. Now, if I notice abnormal temperature readings, I turn on the heater and switch to recirculation mode to divert heat through the AC system, which works as an emergency measure to get to the repair shop. Never push through such problems—BMW N-series engines can warp in minutes if temperatures exceed 100°C.
