While towing 11k up a grade, my F250 2005 diesel 6.0 Truck Whistles. The whistle seems like its coming from behind the Tachometer. Happens on steep grades, close to 5%, with IPR above 74%, Turbo PSI 22+, but usually 28 PSI. ECT is 215 - 220 and then the fan kicks on and won't go up anymore and cools quick. EOT is between 234 and 238 when this happens.
Did a leak check by putting a shop vac blowing into the exhaust pipe and found these leaking and repairs did not help:
-Replaced Exhaust gas manifold and added missing gaskets
-Sealed Leaking Turbo Down pipe
-Sealed leaking exhaust gas manifold to Turbo up pipe. Bolts were not tight.
Whistle is apparent after 5 seconds on the video.
If this link doesn't work, try searching YouTube for "6.0 F250 2005 Truck Whistle" I can't get this video to play from the forum, but it works for me.
When I get this noise, it does not effect power, but I ease off the acceleration, slow down and it goes away. This can limit me to 40 MPH up steeper, extended grades.
No sign of leaking from the degas bottle. I've had heads done twice, second time by a reputable shop.
When I replaced the passenger side exhaust gas manifold, the up pipe on the bottom passenger side where it connects to the manifold had some play to it, lijke a 1/4:" or 1/2". I could wiggle it back and forth. Don't know if this is normal or not, but if I were to point at where the noise seems like its coming from, it would be 2' above this. I can't find any black marks indicating an exhaust leak.
Looking for recommendations on how to proceed next.