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A/C Pulley

2737 Views 10 Replies 4 Participants Last post by  TeflonVixen
I have a 99 E320 4Matic with 182k miles

Little background info, I had an A/C evac/recharge in April. About a month ago my blower motor or regulator went. Haven't figured out which one yet. Last week the idler pulley decided it wanted to snap in half as I was driving to dinner. In the process of it snapping it also shredded the serpentine belt. That was really fun. I fixed that this past Sunday however I am still hearing a rattling sound and another sound I can only describe as sucking air kind of.

I popped the hood and took a listen while it was running. I'm pretty sure the sound is coming from the A/C pulley. Since I have never taken a look at it prior to this, I am not sure whether or not the whole front should be spinning or not as it spins intermittently. Is it supposed to do this? Also, it appears pretty old and I'm sure the previous owner didn't replace it so I'm considering doing so. I guess I just wanted other opinions as I'm only a mechanic through this forum and youtube.


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Hello, What you see that is spinning and then not is the A/C clutch and it does cycle on and off depending on how much the compressor needs to pump the freon depending on demand of cool air. If you are hearing a bearing noise you may need a new clutch, or compressor/clutch assembly. Hopefully someone with more knowledge on this will reply soon.
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