Rites of Summer...Aux Fan Cheap Rock and Roll replacement(an old post from a couple of years ago)

["David A. Leonard" <dleonar1@xxxxxxxxxxxx>]

Dennis asked??>>>

Auxiliary A/C fan Fix/ Replacement question
1.  Is this a common failure?
2.  What are the problems it may cause if I don't fix it?  (I fully intend
to, despite being one cheap b*st*rd, but just curious as to the downside)
3.  Is this something that can be repaired, or does it have to be replaced?
4.  If it has to be replaced, is there a cheaper alternative than buying a
new one from the dealer (used?  a non-BMW replacement?  A cheaper parts
source?)
>>>>>
The aux fan is very important sitting in traffic.. my 88 735i will get
really hot when it doesn't work, sitting in the summer at idle or in
traffic.
  As it a/c season ( I know as I've already dropped $100 on fan control
board this season)
Here is a copy of my answer to the last guy that asked this question.


"How I fixed my 735i fan", by David Leonard.
( September 2000 )

First I drank a beer.

Then I tested the aux fan by removing the grill and spinning the blades.
Bearings smok-ed.

( Blowing BIG 30 amp fuses indicates some serious problems)

Then I removed the engine fan and drained the radiator and took it out and
unbolted the AC condenser, and tilted it back and took off the Aux fan.

Then I called the dealer and was told it was $$450.00.  Bavarian was $350 or
so..YOW..

Then I thought about the universal electric fans you get at NAPA and Auto
Palace For $89.00 for your stock car and RV extra or primary cooling( or the
Chebbie truck)

Then I went to the parts store..they had about 3 different sizes available
Yipee! the 16" universal fan is exactly the same diameter and depth, has a
new shroud, and mounts with special  ZIP ties like you uses on V8 aux oil
coolers fo the Chebby Trucks.

Then I cut off the plug from the BMW fan, and used those really neato
sealant filled heat shrink butt connectors to hook the plug to the new fan.

Then I cut them off and changed the wires so.....
make sure you set the fan to blow air back towards the engine, a pusher
configuration,,they can be set to work either way..read the directions hook
the wires the right way..TEST it before you commit to the snipping of the
zip tie ceremony!

Then I tested the wiring at the radiator temp switch by jumpering the lo and
hi speed connections....
Sucess!  The fan she go!

Then I put it all back together.  the fan should run on low all the time if
the A/C is on, I think it will even run with the ignition switch and AC
button on and the car off .

Then I Drove through Boston rush hour when it was 85 and humid, and my car
didn't overheat !!

Phew!


And that is how I spent my summer vacation.

By Dave Leonard

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