Auxilary Fan- How to tell if it has failed?

[liquidtiger720]

How does one go about testing a failed aux. fan.?

I've searched for some conclusions of known failed fans and symptoms, but haven't found anything conclusive.

My auxilary fan (just after bimmerfest) saw a hot blonde and took a dump or something. When I turn my AC on, it sounds like I'm in a nascar race; grinding or slapping noise that gets tremondously loud and obnoxious.

The AC still works, but I imagine that with the aux fan making that kind of noise (but still spinning)....its not a good thing.


What are your thoughts?

[cschollum]

id have thought any fan manking that kind of noise would be faulty...

[joshua43214]

Pop the grill off and Make sure the aux fan mounts havn't broken. You will have to actualy jiggle the fan frame, the mounts often appear to be good but split when the fan is turned on. Possible the fan is operating, but the mounts are broken or the frame is distorted causing the blades to hit. If its all running freely but makes noise, its bad. I once saw the quick tie for the resistor wires fail and one of the wires was hitting the blades. If you pull the fan, the Plug is behind/under the left side headlight in the engine bay.

AC will operate with reduced eficiency that may not be noticable if you drive on the freeway alot with this fan bad. Not fixing it and running the AC Without good airflow can will cause accelerated refrigerant leakage and may cause weak high side hoses to burst.

[liquidtiger720]

Well, its still running- just makes the stupid noise. I'll take the bumper off soon. thank you everybody.