Hi, new to the forum here, I purchased my 2004 545i about 7 months ago, loving the car so far, had a lot of fun with it. One thing that's troubling me is that every time i start up my car in the morning (just the electronic part, not the engine), the idrive would display "engine overheated", i know the engine is not overheated because it has been sitting in the drive way the entire night, the "overheated" sign would randomly come on after i turn on my engine, but it seems to go away after the engine is warmed up to its optimal running temperature, I took my car into the local shop, they changed all the coolant and temperature sensor, but the problem remains, Im just wondering if anyone had a similar problem, and if anyone have any idea what is wrong with the car before i take it into the shop again, thanks!

 

Dont know If this will solve your issue but when I was getting the warning coming on the idrive the dealer told me the thermostat needed to be replaced, (there was also condensation /leakage around the seal and down the side) so that could be your problem, I'm absolutely a dunce when it comes to car mechanicals so hope this was of some help, either way good luck

 

I also got a new thermostat installed by the shop, and they didnt mention any leakage, maybe ill ask them to look into that, anyway, thanks!

 

The lower sensor triggers (or should I say sends a signal to the Control unit) to turn on the radiator fan when coolant is nearing the threshold. This sensor is located on the lower radiator hose passenger side. Is this the sensor they replaced?

Does the fan go on and off like it normally should? Or does it stay on constantly or is it always off? You may have a fan issue. Good luck

 

Here the job that the local shop had performed on my car so far about this problem: 2 coolant sensors changed at two different place, thermostat was replaced, coolant was checked and topped off, no leaks was found and the engine fan works perfectly normal, it is really weird because as soon as the engine hit its operating temperature, the overheating sign would stop coming on, its funny how it shouldve been the other way around, anyway, they told me could be the cluster fault, but i honestly dont feel like its a huge deal, it is just really annoying for the idrive to tell you that your car is overheating for the first 20mins of driving.

 

There must be some codes present.

 

I do have a oil quality sensor code, plan on getting a new one installed when next oil change is due, i have a question, what does the oil quality sensor really reads? Oil level, Quality of the oil, and the oil temperature? Thanks