RobF15e

I have an issue that I have been unable to solve or find an answer to on the forum, so I am asking for help. My 2007 E-320 Bluetec has started to make a squealing sound that sounds like a belt slipping, but I don't think it is the belt. It only starts after the car is warmed up. When I exceed 2,200-2,300 RPMs when accelerating and only for a second or two. If I let off the accelerator and decelerate, if the RPMs are above 2,000 it will squeal the loudest. I took it up to the top of a local hill and coasted down in 3rd gear at about 35-40 mph and it squealed the entire way down. It was loud enough that people walking turned around an looked. The belt is new as I recently did a bunch of work to the car - oil cooler gasket replacement, swirl motor replacement, a through cleaning of the engine and intakes. The squeal seems to have started a couple of weeks or so after I finished all the work, so it is possible that the work I did caused the problem. Since it started squealing I have removed the belt and cleaned it twice and checked the pulleys. Both seem fine. The car has 98,000 miles. The car will squeal in the driveway if you bring the RPM up to a steady 3,000 and the car is hot. I can hear the squeal inside the car, but when under the hood there seems to be too much engine noise - which also leads me to believe that it isn't the belt otherwise I should be able to hear it when my head is a foot away from it.
I thought I read somewhere that sometimes an intake leak might squeal. The car runs perfectly normal so I have not noticed any drivability issues. As part of my repairs both of the intakes and the turbo were removed. New gaskets where used in the reassembly. The symptoms are so defined that I am hoping someone recognizes them and can point me in the right direction. It isn't the transmission, suspension or wheels since it will happen in park sitting in the driveway. I can replace the pulleys and bearings, but I really don't think they are the culprit since this started too soon after I completed all the work. I will confess that I may have missed replacing an intake bolt, since I had one long bolt left over after the oil cooler gasket repair. But 2 weeks after I completed that, the swirl motor went out (I should have replaced it while doing the previous work I know... So when I took everything apart again, I looked to see where I might have missed the bolt and could not see an empty hole... But that bolt had to come from somewhere... Suggestions? Thanks!

Plutoe

I don't know if you did the following---I assuming that the squeal squeals whether the transmission is engaged or not---if that is correct, mount your girlfriend in the front seat while you are outside with the hood up---in N have her run the rpms up to the squeal zone-----if it does, where do you think the squeal is coming from---if not, drive to a bank and then to a transmission shop!!

RobF15e

It isn't the tranny. Note that I mentioned it will squeal while in the driveway if the engine is reved high enough. Although I didn't specify that the car was in park - it was in park. Thanks for the thought though.

samaritrey

Picture of the bolt? I just did the repair and might be able to help.
Also can you post a video of the noise?

RobF15e

I located the problem. There is a slip collar on the passenger side exhaust just below the exhaust manifold. I had forgotten to tighten it up.... DOAH!!!! I am surprized that it squealed, but since I tightened it up, no more noise.