Got a 528xi 2008, and today my cooling fan turned on after 1 mins (cold start in the morning outside temp 8degree's Celsius). It was on the whole time on my way to work. I started it again after sitting for 5 hours, and same issue. It blasting at full power and not sure why, never seen a warning for HIGH Engine temp as of yet. Any opinions?

 

Possibly a bad coolant temp sensor on the lower hose. This sensor triggers a signal to turn fan on or off.

 

i have about 106000 miles, would you think the water pump is bad? (anyway to test, as i have no code on the dash, and no hidden codes aswell) Also how hard is a DIY for coolant temp sensor?

 

A bad thermostat will throw a code however, I'm not so sure about your electronically controlled water pump. I assume it would since it is an electronic pump. My 545 is a manual pump and the only way to tell is if it starts to make some whirring or rattling (bad bearing) noise.

After researching your engine in realoem it appears you have only one temp sensor at the passenger side upper radiator hose. This is a relatively cheap part and very simple to replace, you won't even have to drain coolant. With that said, considering the mileage on your 5er, I'd recommend you have a coolant drain/refill, and replace associated parts if you haven't already done so. Good luck

 

Could you send me a Realoem link? of where the part is located and the part number :/ ? My car is a 2008 528xi, build 04/07

 

Here ya' go

RealOEM.com BMW E60N 528xi Cooling System Water Hoses

 

Completely dead water pump does not light up the Check Engine light, but does throw a code. Your fan will run continuously, but you also get a message on the iDrive about the car overheating and the car will go into self preservation mode with limited power. I think it cuts off injection to cylinders at some point to keep the engine temperature down and resist overheating the engine. Bottom line, if the water pump is completely failed, you'd not be able to drive the car more than 10 minutes.

 

I am trying the bleed procedure to test if the pump is working. I have my heat setting on high for both driver and passenger side and 1 orange light for fan speed. i don't hear any water movement or pump noise, more over when the expansion tank is open there is no water movement. Also i have a basic code reader and it is not showing anything, but i could see my coolant temp was 111 degree Celsius after 7 mins of driving in city.

 

If it is somewhat quiet, you can definitely hear the bleed happening. Are you sure you initiated it correctly? The motor cycles on and off throughout the procedure.

 

Not entirely sure, i put the key inside and press start without the pressing the brake, then held in the accelerator for 12sec (with the heat in full hot, and lowest fan speed) and I got out and check the bleeding and saw no movement of water nor any sound of water movement. Would you happen to know the proper coolant temp at operating temp?