I have a 2008 F350 6.4 diesel -- I just put on a delete pipe and tuner around 2000 miles ago. It just started to have a whistle sound when I let up on the accelerator. It only does it when the engine gets up to full operating temperature. Seems like it may be a exhaust leak when the metal expands when hot. Has anyone had this same problem?

 

Maybe the connection of the new pipe to the down pipe is loose?

Should be able to see some black smoke marks on the pipe by now, should tell you if there is a leak?

 

+1 - either exhaust or turbo pipe has a small tear in it ????

 

Moved to the 6.4L Powerstroke forum.

 

I'd check those connections but I also wonder if now you are hearing the turbos since you did the dpf delete as well.

 

Have not had a chance to check exhaust, but, I think the whistle would have happened right after the change of the delete pipe. It is a loud whistle /squeal noise when you let up on the pedal after acceleration. It has been about 2000 since delete pipe.

 

Once you delete the beast it will sound like a whistle under normal light pedal and a Jet engine going down the road. Going down side streets or somewhat quiet areas every time you take your foot off the pedal you will hear your turbo winning down, also on shut down if you turn off the truck and don't dillydally getting out you will hear the turbo spinning down.
Music to my ears.

 

^^^ Diddo that.

Roll you windows down, drive under an over pass and let off the accelerator. That will amplify the sound.

 

The same thing is Happening to me. It's a distinctly different whistle than the turbo whitle

 

Try to video tape it

 

Just to let everyone know that the whistle was the cap on the coolant Degas bottle was bad. So, if you have a whistle check the cap on the degas coolant bottle

 

Solved problem by replacing cap on coolant degas bottle, it was bad and caused the whistle