Originally Posted by FWLRmusic

My gf and I just finished replacing the extremely worn out water pump on her X5 with the 4.4L N62. We did our best to bleed as much air out of the system and felt confident to start it up.

As soon as we started it the coolant gauge shot up past the red and stayed there. We dug around and made sure that everything was connected properly.

I used the unlocked dash diagnostics to look at the KTEMP value and while the car wasn't running it read properly. As soon as I started the engine the value read -128C.

We let it come up to temperature slowly and cautiously. The thermostat opened and when we turned the engine off the KTEMP read 103C. But again when we ran the engine the value shot to -128C.

I swapped out the coolant sensor just in case it failed in some strange way but the new sensor acted the exact same way.

Another weird thing I noticed is that the OELTEMP value read "--" instead of an actual temperature.

We tried resetting the ECU through "Test 21" in the unlocked dash diagnostics but it changed nothing.

Anyone have a similar issue? I am going to have to have my indie hook their reader up to it and read / clear the codes. There may still be air bubbles in the system but this is kind of a strange presentation of that I thought.

Thanks for the help!
-Nick