540i

Since I've replaced my thermostat in the winter, I've been tracking my coolant temperature through the Torque Android app and an OBD2 adapter. The information is pulled from the ECU. Can someone tell me the acceptable range for the coolant temperature? For some reason I keep thinking that I'm running too hot. I've also replaced the expansion tank and upper hose in the last few months.

In the winter I was avergaing 96-99 degrees Celsius. Lately, since it's been warmer, It's been about 102-105 degrees. Sometimes it will go up as far as 108. Is this normal or should I be worried? What's an acceptable coolant temperature range for these cars? 108 degrees Celsius is about 226 degrees Fahrenheit....

540i

I should also note that I replaced the thermostat with an aftermarket one earlier this year, but there was a leak coming from the sensor part a month or two later. That is when I replaced it again with an OEM thermostat. Maybe the aftermarket one just opens at a lower degree than the OEM one.

545iMike

My 545i will go as high as 220-225 F on a hot day (95-100 F).

RTR

On my 545i, the temp is exactly the same: 102 - 105 C. 105 at idle and than it drops to 102 when driving. Once stopped again, it goes to 105 in like 5 seconds and just stays there.

If I drive with high rpms for like 3-4 sec, then it starts cooling the engine more aggressively and I've seen it drop to 99 once. Once I was off the throttle, it came back to 102 in just a few seconds.

krzyschicago

Replaced thermo and water pump yesterday in my 545. Afetr warming up temp stays in 101-105 range. I am glad I read here about operating temperature because I would freak out as i still believed temp should bot exceed 90.

Wolrab

I noticed a few days ago that the ring around the tach on my 545i settles down with 5 hash marks showing. It's always shown 4 until now. I suspected the thermostat, so I opened up the hidden menu and eyeballed the coolant temp for a while. It's rock-solid at 102°C while driving, and a bit higher when idling. So this is normal, and the thermostat appears to be doing its job. Anybody got any guesses at why I'm seeing an extra hash mark?