no idlery pulley?
 

I have a 95 325is with m50tu. It makes a "chirping" sound when idling or accelerating at low rpms, especially when cold. Replaced both belt tensioner pulleys and belts this weekend with no change. I noticed when doing it that I have no idler pulley on my car. I'm pretty sure I have a mechanical tensioner like this:

not my car, found this on an e30 forum i'm on (this m50 is in an e30). he has an idler pulley mounted up.
http://i337.photobucket.com/albums/n...7/IMG_1901.jpg

according to realoem this style of tensioner (which is different than the hydraulic shock type also found on 95 m50s) does not use an idler/deflection pulley?

http://www.realoem.com/bmw/showparts...47&hg=11&fg=18

http://www.realoem.com/bmw/showparts...99&hg=11&fg=18

Is this normal?

ok looks like the mechanical tensioner on pre-1995 cars DID use an idler pulley. So it looks like my set up is as it should be.


http://www.realoem.com/bmw/showparts...11&fg=18&hl=42

Does it sound like crickets? You may want to try regreasing or replacing your pulleys. If you have the engine out like that, it's really easy to do. I have the same thing happening in my E39 and it really only chirps at the lower RPMs in drive or reverse.

yes same symptoms as you. did yiu read my post? thats not my engine and i replaced both tensioner pulleys already. i think my mechanical tensioner itself is suspect. i think i may buy a mechanics stethoscope and try to further diagnose it even though the tensioner is only $40.

My apologies - I have quality control issues regarding my replies when a professor is trying to teach me algorithm design and I'm here trying to find resources on greasing pulleys. :thumbup:

If you search "re-grease 3 belt pulley bmw," you should land at a link that has descriptive pictures of all the parts connected to the belts. I bought some wheel bearing grease from O'Reilly's and I'm going to attempt to perform the "regrease" tonight.

Have you considered just greasing all of the pulleys? Once you remove the fan shroud, everything's there and really quite easy to remove and inspect. There's a good DIY on removing the shroud from Beisan Systems. Once you find a pulley that has bearings with play in it, you've isolated one of the culprits. From what I've read over the last several days, this symptom seems to be caused by the idler pulley. Other symptoms I've read about are constant and include noise in any gear - my car doesn't make a noise when it's in park or neutral, so hopefully that's the case.

once again... i've replaced both pulleys. my car doesn't use the third idler pulley found on most other versions of these engines therefore i don't have one...

Well, I think the alternator bearing can also cause this noise?

i'll report back if i make any findings!

So i bought a mechanic's stethoscope and placed the rod on the tensioner with the engine running. there is a pretty loud noise coming from the assembly, like something banging around inside (no its not my vanos lol). anybody know what one of these things look inside and what could be broken?

Maybe...

YOU SHOULD CHECK, INSPECT, REPLACE THE TENSIONER.

lol... im just trying to proceed carefully, in the past ive thrown parts at problems before and it just ended up being misdiagnosis. doing research it seems like this is not a very common problem.