Cooling System Maintenance Questions

[ThrasherFan]

2002 4.4i out of warranty with 56K miles. Planning on a DIY cooling system overhaul including water pump, tstat, expansion tank and all hoses. Couple questions for anyone who has done this themselves or had it done for them:

1. Did you replace radiator? My sense is that if I'm doing everything else, might as well replace rad as well since it needs to be pulled to get to pump. Looks like it will be the single most expensive part of the overhaul.

2. It looks like there is water pump for the heater and Ac system; part 13 in link: http://www.realoem.com/bmw/showparts...64&hg=64&fg=18. Did you replace this? (BTW - I had hoses 11/12 replaced when the Valley Pan Gasket was replaced and I am planning on replacing hoses 5-6-7 with all the other hoses.


3. There are twp thermostats. One attached to the water pump and a second one that looks like it might be part of the Heating and AC system - part 15 in link: http://www.realoem.com/bmw/showparts.do?model=FB33&mospid=47746&btnr=17_0183& hg=17&fg=05. Did you replace this?


Based on RealOEM prices, parts cost looks like it will be around $1500 including rad replacement and. I'll be using parts from dealer and with my car club discount I've generally found my local dealer prices to be lower than what RealOEM estimates. Thanks in advance for reponses and any recommendations or comments.

[fast4d]

I've had luck with bmw waterpumps. both our cars' original lasted till I replaced them at 100k miles. your expansion tank will likely weep before 100k.

I would just replace the main upper and lower hoses that goes to/from the radiator. the other parts can wait.


I did the radiator/waterpump/valleypan plus 90% of the hoses at 100k miles.

[Zulu95]

Do not trust the OEM pump. I had my pump start failing at 38k. Others have lost engines when they had total failure on the move. Bavauto.com, among others, have a race ready after-market pump.
When you get the junk above click on the "Warning triangle" in the top right of the message box.