POLL: E39 aux cooling fan behavior

If you would take a couple mins to take this poll, I thank you...

The aux cooling fan "noises" here refer to noises you hear from inside the cabin from the electric motor itself, not wind or air noises (sounding like a truck or bus) from the fan...

1. does your aux fan make a growling or whining noise when it is starting up. How would you describe it?

2. Does your aux fan make spinning-down whining or siren-like noises when stopping. While the fan's RPMs are spinning down, are there multiple moments where the noise seems to get louder (almost like "harmonics").

3. If yes to either of the above, have you noticed if the noises are easier to hear inside the cabin or outside

4. When your aux fan is running at a typical medium speed, does its motor make noise that is louder than an idling engine from inside the cabin.

5. When the computer tells the aux fan to stop from a typical speed, how long would you say it takes your aux fan to spin down

6. When you shut the engine off, is the aux fan spin down seem longer or shorter than 5 above

7. When was your aux fan installed? What's your car's model & year?

8. Is it your aux fan original or a replacement. If replaced, do you know what brand.

9. If replaced, is your replacement quieter/same/louder as the original aux fan motor.

10. Do you know if your aux fan motor itself has a made in Canada, or made in Mexico sticker on it.

Ed in San Jose. BMW CCA member since 1987 (Nr. 62319). Golden Gate Chapter. '97 540i 6 speed. Build Date 3/97. Aspensilber over Aubergine leather.
http://forums1.roadfly.com/preferenc....php?img=21320

on a M52 engine that has lost coolant

"[Oops!] on a bull material"

Sounds like you have a bad bearing allowing for the harmonic convergence. Sounds like your motor is making winding contact once the copper is heated up, so it's noisy. Or there is a queen of hearts clothes pinned to the shroud.

My fan, which I installed 18 mos ago, is OEM of unknown origin, isn't noticed when running unless I listen for it, and when I notice it the sound is not unlike the sound of a fan moving a bunch of air. When I shut the car down it shuts up. Perhaps the roar of the mighty V8 inhaling through a sewer-pipe-sized intake and breathing freely through a huge exhaust with minimal restriction masks the sound in a delicious way (my apologies, Euro).

'98 540

I am on my second BMW OEM cooling fan this week, and both make whining noises that weren't there with the original fan (when it was working) and really get annoying after a while. I can tolerate fan blade noise, wind noise, etc. but not whining/siren from what sounds like a cheap fan motor - particularly not on a solid car. I'm trying to determine if BMW is shipping aux fans with what should be considered defective motors.

And it's two whining fans in a row like this. Trying to sort out if BMW has a new fan motor issue.

Maybe you could return the second one and then call various parts sellers to see whether someone has a fan from a different supplier. Parts are always getting moved to lower cost suppliers, especially for our relics. Finding someone with an NOS fan would be ideal.

Yes they are from the same dealer. Discussed with them the idea of transferring a fan from across the country and hopefully get a different batch. The poll was to see if I was the only one experiencing this currently.

I heard it from inside outside but sitting next to it like today, its horrible.

Its not new but not original either, I think it was replaced with the radiator around 2004-2005.

Its a shame how loud they are. I will try and universal electric fan which is much quieter - for example Zirgo.

I'm going to try to get BMWNA and or perts suppliers to solve this problem. It doesn't sound like a bad batch problem - but sounds like a bad design or more likely poor sub component selection. Simply put- when we purchase a BMW OEM part, it should operate to the same standard as the original part.

NOS parts are typically old inventory that hasn't moved off shelves. Slower dealers may have NOS parts. In your case it appears a more recently selected supplier of cooling fans doesn't make them as quiet running as the original supplier. A NOS fan of original supplier origin may solve your issue. The best way I can recommend you to proceed is to determine who the supplier is of your fan and then call around until you find someone with a fan that is from a different supplier, hopefully the original supplier.

in my 540. Build date is Feb 2000. I wouldn't consider it quiet by any means. IIRC your car is a few years newer.

http://home.comcast.net/~jimlev/AuxFan2.JPG

Dakota tribal wisdom says that when you discover you are riding a dead
horse, the best strategy is to dismount. However, we often try other strategies with dead horses, including the following:

1. Buying a stronger whip
2. Changing riders
3. Saying things like "This is the way we always have ridden this horse"
4. Appointing a committee to study the horse
5. Arranging to visit other companies to see how they ride dead horses
6. Appointing a team to revive the dead horse
7. Creating a training program to increase our riding ability
8. Comparing the state of dead horses in today's environment
9. Pass legislation declaring that "This horse is not dead"
10. Blaming the horse's parents
11. Harnessing several dead horses together for increased speed
12. Declaring that "No horse is too dead to beat"
13. Providing additional funding to increase the horse's performance
14. Authorize a study to see if contractors can ride it cheaper
15. Procure another dead horse
16. Declare the horse is "better, faster and cheaper" dead
17. Form a quality circle to find uses for dead horses
18. Revisit the performance requirements for horses
19. Say this horse was procured with cost as an independent variable
20. Promote the dead horse to a supervisory position


<img src="http://members.roadfly.org/filehorse/SigPic 2-26-05.jpg" height=225 width=300>

Filehorse
Knoxville, TN
BMWCCA #407627

2002 525i Steptronic Sport/Premium | Build Date: 05/02
81,000 Ultimate Driving miles
Xenons
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Steering wheel position memory w/Alzheimers
"Lifetime" ATF replaced at 40,000
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2001 E46 325i (Jet Black) Forced Retirement 6/28/09

2001 E46 325i (Orient Blue) Forced Retirement 10/09

1989 E30 325i (Alpine White) Retired