Ok i have been using the search function trying to nail down every possible thread regarding -03 6.0's with whistle issues. Long story short, after i installed the full 4" turboback my truck has been whistling a lot, too much for me to be happy with it, i am trying to find the solution on making this go away. A few things that i am aware of:
* 2003 6.0's are more intended to whistle due to the turbo design. Question is if mine has another issue making it whistle even more? The noice is very annoying inside the cab during boost/rpm build up, once you dont spool the turbo/load the motor its fine.
* I have read about leaky Y-pipes, degas bottle caps, blown EGR gaskets that can cause increased whistling, i tried removing the degas cap completely and run the truck a short distance with no difference. I cannot see or hear any leaks from the Y-pipe, is there a good procedure on how to check this? EGR Y-pipe plate "thingy" was installed during the 4" exhaust installation and the kitty was not reinstalled as well.
It all comes down to that this started when the exhaust was installed and i am puzzled no matter to that this is normal 2003 open exhaust whistle or if its an unlucky combination of something failing/leaking/draining etc during the time it got installed.
Question is, where do i start? putting another muffler on to see if the whistle decreases? start looking for issues with leaky pipes etc? I need some input on this matter.
Sorry for the long thread but thank you if you have read it this far!!