Reasons for BMW's Low Oil Temperature Not Rising Even After Prolonged Driving

[DiIsabella]

Here are the reasons for BMW's low oil temperature not rising even after prolonged driving: Thermostat malfunction: Keeps the coolant in a large circulation state. Electric fan control issue: Continuously operates at high speed. Distorted signal from the water temperature sensor: Causes inaccurate operation of the thermostat and electric fan. DME not receiving the current signal feedback from the water pump: It assumes the water pump is not working. To protect the engine and prevent overheating, it puts the water pump into emergency mode and turns on the electric fan, resulting in consistently low oil temperature. Oil temperature range while driving: High-speed driving oil temperature is around 110°C, while low-speed or idling oil temperature is 95°C+.

[Noelle]

I've driven quite a few BMWs, and there are usually several reasons why the oil temperature remains low for a long time without rising. First, the thermostat is stuck in the open position and cannot close to allow the coolant to heat up, causing it to circulate too quickly. Faulty temperature sensors are also common—BMW's electronic systems sometimes display incorrect temperature readings. If the oil level is too low or the oil used is too thin with insufficient viscosity, it's also harder for the temperature to rise. Driving at low speeds for extended periods, especially in the city, puts little load on the engine, making it even harder for the oil temperature to increase. These issues may stem from design flaws in BMWs, with some models like the older E-series being prone to thermostat problems. I recommend taking it to a professional shop for inspection, using a diagnostic tool to read fault codes, and replacing the thermostat or sensor if needed. Low oil temperature is bad for the engine—insufficient lubrication can lead to bearing wear and higher fuel consumption. Addressing it early will save you trouble.

[McAllison]

From repair experience, the root cause of low oil temperature in BMWs is often a thermostat failure stuck in the open position, preventing the coolant from reaching normal operating temperature. Faulty sensors can provide false data, showing low oil temperature. Insufficient oil level or incorrect oil grade, such as using a low-viscosity type, can also slow down heat buildup. Cold external environments or prolonged low-speed driving exacerbate this issue. Certain BMW models, like those with the N55 engine, are prone to thermostat failures. Diagnostic tools are needed to confirm if sensor outputs are abnormal. Check oil level and type, and consider switching to a higher viscosity oil if necessary. Prolonged low oil temperature can damage the engine, reduce lubrication effectiveness, and increase wear risks, so don’t delay—address the issue promptly to avoid bigger problems.

[MarleyRose]

Friend, your BMW's oil temperature won't rise? The thermostat being faulty is the most common issue—it stays open and prevents heat buildup. A problematic sensor might falsely report low temperatures. Low oil level or oil that's too thin can also affect heating. BMW's electronic systems occasionally act up. If it stays cold even during prolonged highway driving, it accelerates engine wear. Just replace the part and recalibrate—it's cost-effective and hassle-free, so get it done sooner rather than later. Don't underestimate this issue; insufficient lubrication can quickly damage components. It's more noticeable during city driving, so it needs to be addressed.