Very loud clanking noise from engine, belt drive - compressor?
Whenever the rpms are low like below 800 ( if I put the car in gear (drive or reverse) and I am on the brakes or when I come up to a stoplight), And the A/C is ON , I get this very loud clanking, vibrating and squealing noise from right around the supercharger / belt tensioner pulley and possible the ac compressor. The entire supercharger and air box vibrates like crazy, and if the car is cold enough or the rpms dip enough, it makes a wicked squeaking, like either a seized serpentine belt pulley or something.
This is definitely coming from the front/drivers side engine area...not weak clicking from the a/c vents that alot of people experience.
Weird thing is, the car made this noise before and I thought it was the ac compressor as it went out and then stopped blowing cold. But after replacing the ac compressor (which now works and blows cold air) the noise is still their and maybe even louder.
If anybody has experienced this or has any ideas, please let me know before I start tearing apart this car.
Thanks,
Robert


When the bearing starts to go really bad, you hear it all the time.
Try taking off your serpentine belt, and spin all the pullies. if it makes noise, it needs to be replaced.
if not, the pulley will eventually seize and play pin ball with your engine bay.
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On most cars, the ecu kicks up the rpms a few hundred when the ac is active, but this car doesn't...
When the bearing starts to go really bad, you hear it all the time.
Try taking off your serpentine belt, and spin all the pullies. if it makes noise, it needs to be replaced.
if not, the pulley will eventually seize and play pin ball with your engine bay.
Maybe what's happening is that this bad pulley seizes at the low rpm causing the squeak and noises.
I'll check those pulleys again...
I can firmly say the tensioner is very stiff and not a culprit.





I too was worried about the a/c but it wasn't.

On most cars, the ecu kicks up the rpms a few hundred when the ac is active, but this car doesn't...


I would have to respectfully disagree with you on this one. True, the noise could be comming from either the tensioner or the idler pulley. I have replaced my idler pulley even though it rotated fine. The tensioner spring is tight with and the pulley has no play.
My researching leads me to believe that the noise is stemming from the alternator (sprag bearing or alternator pulley). As that bearing or pulley binds, it places undue stress on the AC compressor, eventually causing the plastic to break and allow the ac pulley to rotate freely.
For some reason, there are far too many MY2005 W203s with this problem, so I wouldn't call it a random event. When I get back in town from work, I am going to the dealer an have a MB look into the problem. If it is not resolved, I am going to get MBUSA headquarters involved.
-Paul
I would have to respectfully disagree with you on this one. True, the noise could be comming from either the tensioner or the idler pulley. I have replaced my idler pulley even though it rotated fine. The tensioner spring is tight with and the pulley has no play.
My researching leads me to believe that the noise is stemming from the alternator (sprag bearing or alternator pulley). As that bearing or pulley binds, it places undue stress on the AC compressor, eventually causing the plastic to break and allow the ac pulley to rotate freely.
For some reason, there are far too many MY2005 W203s with this problem, so I wouldn't call it a random event. When I get back in town from work, I am going to the dealer an have a MB look into the problem. If it is not resolved, I am going to get MBUSA headquarters involved.
-Paul
I would have to respectfully disagree with you on this one. True, the noise could be comming from either the tensioner or the idler pulley. I have replaced my idler pulley even though it rotated fine. The tensioner spring is tight with and the pulley has no play.
My researching leads me to believe that the noise is stemming from the alternator (sprag bearing or alternator pulley). As that bearing or pulley binds, it places undue stress on the AC compressor, eventually causing the plastic to break and allow the ac pulley to rotate freely.
For some reason, there are far too many MY2005 W203s with this problem, so I wouldn't call it a random event. When I get back in town from work, I am going to the dealer an have a MB look into the problem. If it is not resolved, I am going to get MBUSA headquarters involved.
-Paul

I would have to respectfully disagree with you on this one. True, the noise could be comming from either the tensioner or the idler pulley. I have replaced my idler pulley even though it rotated fine. The tensioner spring is tight with and the pulley has no play.
My researching leads me to believe that the noise is stemming from the alternator (sprag bearing or alternator pulley). As that bearing or pulley binds, it places undue stress on the AC compressor, eventually causing the plastic to break and allow the ac pulley to rotate freely.
For some reason, there are far too many MY2005 W203s with this problem, so I wouldn't call it a random event. When I get back in town from work, I am going to the dealer an have a MB look into the problem. If it is not resolved, I am going to get MBUSA headquarters involved.
-Paul
Last edited by Glyn M Ruck; Sep 5, 2010 at 10:43 AM.
https://mbworld.org/forums/c-class-w...8l-c230-2.html

Last edited by e24kgold; Sep 14, 2010 at 09:58 AM.
But I did happen to get the tensioner pully off today, seperate from the tensioner bracket....without all the work. I also bought a new idler pulley and complete alternator...
Hey e24kgold, did you have the wicked noise were talking about? Why just the alt pulley and not the entire unit, as many say the issue is in the bearings, the "sprag" in particular.
Any way I have update pics here




