Would a bad EGR valve cause a loud squeal at idol and go away as you accelerate. Sounds like a belt squeal but I have removed all the belts and it sounds like it is coming from the EGR area as best as we can tell.We have used a mechanics stethoscope but can not exactly pin point where its coming from.
Does it have a gear driven air compressor? I've had a compressor go bad and make a horrible noise similar to what you're hearing and then go away with accelerator.
Edit: My bad, failed to read the title. Maxxforce 7 does not have a gear driven air compressor.
Could possibly be a boost leak. Check CAC hoses for leaks or tears.
I'll have to second the boost leak. We had one about a year ago make a noise like that. I was the hose from the turbo to the CAC. A bolt rubbed a hole in it.
Maxxforce 7 EGR valve
Posted - 01/14/2016 : 1:10:40 PM
