96 S500 Idler Pulley/Smog Pump
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96 S500
96 S500 Idler Pulley/Smog Pump
I've been having a "high pitch" sound coming from my vehicle. For such a long time I thought it was my tranny because the sound is "synchronized" with every gear shifting. It also synchronizes with the engine like it's all "one" entity. So when I accelerate the "whinny" (not squeaky) sound gets higher. It's totally in synch with the engines every move speeding up & slowing down. So I took it to "Mr. Transmission" and they drove tested it and said the tranny is fine, has 190K on it. Had to believe them because what transmission place turns down $$$$. So after being perplexed I took it to another transmission shop and told him my complaint. I started car and he noticed the sound immediately. He put the "stethescope" on both side of engine while I pushed on gas pedal and said the high pitch sound is coming from my idler pulley area. Said it was so high with the scope on, he had to remove it from his ears In my opinion it sounds like a "bearing" is worn and not the pulley. I replaced serpentine belt about 500 miles ago and all the pulleys were tight. note: the sound was present even when I changed the belt but just didn't know what it was because I was just stuck on it being the tranny.
QUESTION: Should I just replace the pulley OR should I replace the entire Air/Smog pump with clutch & pulley? Would hate to replace pulley only to find out the "entire" assembly needs to be done. Any feedback from my Mercedes Benz family is appreciated!!
QUESTION: Should I just replace the pulley OR should I replace the entire Air/Smog pump with clutch & pulley? Would hate to replace pulley only to find out the "entire" assembly needs to be done. Any feedback from my Mercedes Benz family is appreciated!!
Thread Starter
Junior Member
Joined: Oct 2011
Posts: 20
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96 S500
Hey, thanks for the reply. However, didn't see any information attached except "1999 S 320 nitrous, 300sd not stock" in the reply section? oh...and that you changed yours at 150k miles. Outside of that i didn't see any additional information. Can you resend? or elaborate? Thanks
Thread Starter
Junior Member
Joined: Oct 2011
Posts: 20
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96 S500
So based upon my description of the sound etc.....you think I should replace the "pulley" ONLY or the ENITIRE smog pulley air pump component which consist of pulley? What do you think? Just wondering got a guy parting out another 90 S500 what will sale me entire pump for $150 if I pull it. He's got 78k miles on his. Let me know what you think? Thanks
