2008 528i N52K Bleeding and Running Temperatures
 

Hey guys, just wanted to share this because I got stuck and hopefully it can help everyone. I recently replaced my thermostat (got too low of a temperature code) and replaced the water pump alongside it as a precaution, water pump turned out to be original from the factory, surprised it still was running at 158k miles. However I could not initiate the bleeding procedure! Turns out it got initiated after I went into the climate settings, turned on heat to red, and put one bar into each direction slot for the motor; there are 3: 1: top (windshield), 2: middle(cabin), 3: low(legs). After setting those three at low fan speed, and climate to red, and temperature knobs to high temp with main fan blowing at low, the bleeding was able to start! Before I have done the direction fans, it would not work, so try this if the bleeding procedure does not initiate.

Also it is possible for this procedure to be done without a battery charger (I charged the battery at auto-zone for free) and it was okay, however constantly trying to start the bleeding procedure before it worked drained the battery so be careful trying over and over or it will drain the battery.

I also took note of the temperatures before and after the thermostat was replaced for anyone that may need it:
Before (Thermostat was stuck open)
Normal engine:
75-85 degrees Celsius - would only go up to 100 degrees Celsius if in traffic, but would rapidly decreased to 75.
Normal engine + climate control
70-80 degrees Celsius

After (Thermostat was changed)
Normal Engine
102-104 degrees Celsius
Normal Engine + climate control
96-104 degrees Celsius

If I got something wrong, let me know so I can change it, thanks in advance hope this helps!

i do this occasionally while waiting for my GF to do around-the-town stuff, but just for posterity, the procedure I do when bleeding is what I remember reading on pelicanparts. i don't mess with the idrive settings, just one click on the fan dial, full temp on both other temp dials, hold down the throttle for 10 seconds and you can hear the whirring of the water pump. timer set to 12 minutes and turn everything else off afterwards. don't forget to fill.

my running temps are about 96 C fully warm to about
96 -103 C Normal Engine ( no climate control)

That is exactly what I was doing but it would not initiate, but after setting those 3 fan settings it started, I guess mine worked differently? But just thought I would post it in case someone else encounters the same problem as I do and they could try it.

This is my current temp right now, I do think I might need to change the tstat. Did you get any code when it was stuck open/before you replaced it?
Mine isn't showing anything, it's like as if the tstat is working fine at the beginning but once it opens, it just stays open till the engine is off.
Oh, having bout 115k on it and I am getting pretty bad fuel consumption too.

Yes, I had the code: P0128 Coolant Temp Below Thermostat, and so on. It is not a major code so it will not trigger a warning like a high temp. coolant would in your iDrive, however it would still give you a Check Engine light so that is how you know something is there. Scanning it gave me that code so I would suggest to start from there.

Strange, no codes or whatsoever. I did have it connected to INPA and nothing, nothing on the iDrive too and no CEL at all. :confused:

Well if no codes are present then the temperature may be good for the place you live in? I read somewhere that the computer adjusts based on environmental temperatures.

You can always just replace the thermostat and see. I found mine to be original and surprised it lasted 10 years in such heat here in California.

i'm getting horrendous gas mileage so no, i'm pretty sure that it's pointing to thermostat.