In Reply to: E38 Fan Noise? posted by Kevin on June 29, 2001 at 08:08:43:
This is a re-post with a different subject to try and attract more response (just got one before -- thank you, whoever that was). Maybe my hearing is too sensitive, but as I get older, everything else has fallen apart, so it's hard to believe my ears are any good.
I seem to have a "howl" on a 1999 740iL that goes in time with engine RPM. Sounds kind of like a fan on a big Suburban, but you can really only notice from inside the cabin. Sometimes you can feel the slight vibration in the shifter handle. Can't decide if it is transmission related or engine fan related. Doesn't always seem to be noticeable. I hate to turn the radio up to fix. Has anyone else noticed this? Is it normal? After you've had a car for awhile, sometimes you get more sensitive to noises that you didn't notice at first. I haven't talked to the dealer yet -- hate to cry wolf.
If you feel the noise is coming from the fan it may be the fan clutch. The clutch is suppose to regulate the spinning of the fan at acceleration. If the clutch is bad the fan will spin as fast as the engine is turning causing a howling sound.
Things to check.
Sitting still at idle accelerate the RPM's. Does the sound become more noticable at acceleration?
Second, open the hood and accelerate the car is the noise coming from the fan. If you only hear the noise at certain times that means the clutch is occasionally working.
If car is under warranty have it fitted. Forget about crying wolf because when the warranty expires you will be just crying, if you wait.