Little help please

[JohnWayneC]

Hey guys I have an 05 SD with the 6.0 and sometimes when I am driving the boost drops I hear a loud fan type of noise like escaping exhaust or something. Then it stops and the boost goes back up. It usually only last a minute or two and it doesn't do it very often. It sounds like a waste gate or something opening and letting the boost drop off. I am not sure if thats even possible thats why I ask you guys. Any suggestion or help would be greatly appreciated. Thanks, John

[JohnWayneC]

Anybody care to guess what may be going on it did it again today twice? Both times it lasted a coulpe of minutes the the loud fan type of noise stopped and boost went back up.

[purplehorn1977]

almost sounds like you have a wire harness problem. ITs sending a signal to the fan ans dropping the signal to the turbo. but not for sure. it could be a sensor going badd its thinking that air temp is to hot and dropping boost and turning on the fan to cool air charge.

[JohnWayneC]

Thanks at least it's a direction to look into. The loud fan type noise I hear when it happens is not the cooling fan. It sounds louder and like it's dumping boost instead of holding it. Kind of like a waste gate or something opens and blows the exhaust out and dumps the boost, not sure. Anybody else?