I have a 2007 6cylinder flex fuel 3500 series engine. I've had a whir/whine going on under the hood for awhile now and attempting to troubleshoot the issue. Things I've done:

1) remove belt and start. No whine, so it's definitely something the belt is moving. Replaced with new belt and problem still there.

2) replaced power steering pump and water pump. issue still exists.

3) I've performed some rudimentary troubleshooting by using a screwdriver and listening to the moving parts. I don't believe it to be alternator.

It really sounds like it's coming from the front of the engine. I pulled off the front idler pulley and that is running true.

Upon a little bit closer examination, I believe it to be the air conditioning compressor. There is some slight play in the plate that sits against the pulley.

What are my options? Replacing that entire unit is pricey. If i can have the assembly rebuilt, i'd be happy with that. I'm just unsure of my options. Can i purchase a bypass pulley for that unit? I don't care about A/c.

Also, how in the heck do I get down there to work on it? It's in a really tight spot.

thanks!

 

I was wrong. did more investigation and it looks like an OEM issue.

same as my friend over here.

https://montecarloforum.com/forum/ne...ote=1&p=649698

 

Does the sound go away if you turn the AC unit on?

 

No. After some additional investigation, I do think the source is still related to the power steering somehow. Even with a pump replacement.

 

I had that a whine in my 06 3.5L, mine went away after having the power steering pump replaced by the dealer and flushing the power steering fluid.

Did you use a genuine GM part when replacing the power steering pump? Maybe the new one is a dud.

 

I bought an aftermarket pump from advanced auto parts. I installed it, still had the whine. I thought that might be the issue, so i did a defective return and got another one. Still have the whine.

I have not performed a full flush. Thinking i'll take to a mechanic, have him inspect the lines and perform that flush for me. If still an issue, maybe order an actual AC delco pump?