Annoying Engine Rattle Issue

[scorn6]

I've been meticulously restoring, upgrading & maintaining a 94 325is w/ 130K since this past September. Ever since I purchased this car I've been plagued with an incessant engine rattle which seems to stem from one of the external components mounted on the front of the motor. It only rattles during idle mode and will halt at the slightest RPM increase which leads me to believe that it is surely belt-drive related. However, a check of all belt driven components shows everything tight and in proper working order.

I've changed the belt along with the idler pulley but am reluctant to to change any additional componenets due to the fact that they are all working properly and a trial and error check could turn out to be a complete waste of money. I'm a hard core DIY'er but simply loath the thought of having to take it to a shop.

Anyone else here had a similar issue in the past or any reasonable suggestions? This is really driving me nuts.

Regards,
scorn6

[NeverLeaned]

My 96 Impala SS's belt tensioner bearings would go every 10K.

This is actually do in fact to a slight misaligment GM made when they designed the alternator brackets...... Thats GM for ya! :P

The bearings would go premature... but the sound was masked by the chirping noise the belt would start making. The GM dealer would always replace the tensioner and the belts to remove the problem under warrenty.

I doubt you are having the same problem, but perhaps my little story will give you some new trains of thought on the matter.

Good luck

[ridikuledind]

Mine does that same thing and i cant figure out what it is. I changed all of my belts and all of the pully's, but the noise wont go away. I also changed the clutch fan because i thought that might fix it, but it didnt. if you figure it out let me know because i think it makes my car sound like crap...when its ideling.

[93 325i]

By the description i'd say VANOS. The location of the sound is right and I know a VANOS makes a rattling sound when it gets worn.

[4evrwyntr]

A longshot - it may be the brake calipers. Granted, not on the engine, but they are in front of it. These could rattle at idle.

[vincentwashere]

Originally posted by 93 325i@Apr 20 2005, 08:34 AM
By the description i'd say VANOS. The location of the sound is right and I know a VANOS makes a rattling sound when it gets worn.

[snapback]335320[/snapback]

agreed. its either rattling or ticking. u can hear it right above the fan. its rather expensive to fix. the unit was 200 dollars with discount at dealer, and 700 for labor. please do not replace it yourself if u dont have the special bmw tools. my friend did that and he almost had to buy new cams and shit. and his compression was all funkd up

[ridikuledind]

Whats the VANOS?