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View Full Version : what could cause AUX fan vibration ?


Chad535
06-10-2004, 01:49 AM
This was realy strange...i had this intermittat vibration problem long ago and i had attributed that to every possible thing...injectors, faulty sensors, engine mounts, gear mounts , or simply tuning. till yesterday when i relaized after a long drive that after switching off the engine and then going back to the ON (that is where the AUX fan continued spinning with the engine off) that the vibration came with the engine off. Well, this is the new fan sinece the old one had siezed a long time ago and had to be replaced and the problem used to be there also with the old fan.
anything special to check with the fan ?. could the problem be coming from the radiator ?. it looks firm.
winfred
06-10-2004, 08:53 AM
make sure it doesn't have a squirl stuck in it?!
dca
06-11-2004, 03:44 AM
it is just a fan, if its bearing is not good, it may cause vibration, also if fins were not placed properly during production fan might be unbalanced.
Unregistered
07-13-2004, 04:43 AM
To check if it is the fan that causes the vibration you can have the engine running, hold the fan and manually rev up the engine. If there is still vibration you know it is not the fan,....and vice versa.....
TimGinCentralNJ
07-13-2004, 08:00 AM
...wasn't so bad at low speed, but unbearable at high speed.

Hope that helps,
Tim G.
'91 535iM
120k


This was realy strange...i had this intermittat vibration problem long ago and i had attributed that to every possible thing...injectors, faulty sensors, engine mounts, gear mounts , or simply tuning. till yesterday when i relaized after a long drive that after switching off the engine and then going back to the ON (that is where the AUX fan continued spinning with the engine off) that the vibration came with the engine off. Well, this is the new fan sinece the old one had siezed a long time ago and had to be replaced and the problem used to be there also with the old fan.
anything special to check with the fan ?. could the problem be coming from the radiator ?. it looks firm.
Gooch
07-13-2004, 08:33 AM
You may notice a small metal clip on one of the blades. Mine rusted off. I figure it was to balance the blades during rotation much like a tire.