Well, I have been driving with no fan since that post and we are finally seeing some warmer days here. I am happy to report that the stock aux fan does more than enough to keep the engine cool!
Few things to note:
- The longest i sat in stop and go traffic was ~40 minutes and it was ~25 celcius outside
- Since i still have the stock coolant temp switch (fan switch) the engine heats up to the 3/4 mark on the guage before the high speed kicks on.
- If i press the A/C button the low speed setting of the fan is engaged and the engine NEVER crawls past the 1/2 way mark on the guage
- There was no need to have my fan on unless i was sitting in traffic for over 15 minutes. The high speed setting (when i let the engine reach 3/4 on the guage) would bring the temp back to 1/2 within a minute.
Compared to when i took the fan off last year I am seeing a significant increase in cooling now that there is no A/C condenser in front of the rad.
For reference, i used the OEM euro brackets to mount the aux fan which i purchased from BMA auto parts for about 10-15 bucks for the bigger two and under 5 for the small cup.
There was no re-wiring and I was able to use the old hardware on the fan to install it to the brackets. I needed to by two speed nuts to skrew the mounts on the top of the rad support. If I remember, I will take a few pictures of the fan on my car tonight. I also did
not use any water wetter or any similar product or run a cooler thermostat.
Seriously, this has to be the easiest mechanical thing i have done to the car to date and one of the more satisfying ones. To get the fan in/out I undid the upper rad support then lifted the rad and pulled it toward the engine. The rad has rubber bumpers sitting in cups on the bottom to hold it in place so it is easy to reposition afterwards. The hardest part was jamming the rubber peices into the mounting brackets.
Here is the picture: The two upper brackets needed to be swapped on my car for some reason since they didn't mount the fan properly the way they show them to be mounted.
http://www.realoem.com/bmw/showparts.do?model=1111&mospid=47263&btnr=17_0073&hg=17&fg=10