07-17-2013, 10:28 AM
Officially Welcomed to the 'Fest
Location: Ft. Lauderdale and Connecticut
Join Date: Feb 2004
Mein Auto: 2007 530
A couple of comments, after doing this job yesterday (bad pump, PM the thermostat since I was in there) on my 07, 65K mi E60.
First, the pump control electronics are what fails. Other sites note that intermittent codes are sometimes thrown prior to failure, but realistically you'd need to regularly check the codes in memory every so often, since no one has seen the check engine light go on solid in advance of a "achtung! Stop zee effing car right now!" dash warning.
That said, you can confirm pump failure by trying to start the bleeding routine. It won't start. If you want to confirm it, put a meter on the pump control line while the bleed routine is running and you'll see +6VDC on it, but the pump still won't run. If these are your symptoms, you can be confident that it's a failed pump.
Electrical diagram below. Navigate to engine cooling for your year E60/61 and you'll find wiring color coding, fuse location and control line location. Do yourself a favor and check the fuses before you climb under the car.
Second, the above writeup is really well done, so if you use it this is a straightforward but fiddly job for a confident shadetree mechanic. But, I don't recommend it as the first repair you decide to do on a car. You really don't want this job to fail again because of a loose clamp or improperly seated hoseclip...
Third, pump and thermostat are probably a $900-1000 dealer job. DIY with parts from Pelican and Bav Auto are $450-500 or so net of shipping.
Couple of cooling system diagrams attached, as well.
Again, absolutely a great writeup, and it will guide you through the process if you decide to attempt it. Good luck.
2003 325XI (gone)
2004 530I (gone)
2001 530I (gone)
Last edited by banglenot; 07-17-2013 at 11:07 AM.