Loud turbo whistle/whine when when motor is under load!

Could be possible its getting ready to croak. Don't wait to long to have it checked out though because turbos are super expensive to replace but so is the tow bill if it happens on the road plus normally when a turbo goes out, it will suck all of the oil straight out of the motor and spew it out of the stack and all over the cab. Seen it happen many times. But thats just an idea, it could be just an internal part.

 

All the hoses and tubes have been checked for leaks?

 

that's a boost leak.

 

Sounds like a loose clamp.

 

check the boots between the turbo and the charge air cooler. they are down at the bottom of the frame in the front, and exposed to easy damage from road objects. As well, and/or a clamp could be loose or weak. Some soapy water in a spray-bottle can help you find a leak while the truck is idling. Check all the hoses and joints, both on exhaust and intake side of engine.

 

If its not those boots ck the csc I think thats whats its called I had a large crack by the radiator its cast iron when it cracks it lets air in and runs like crap. I had a new turbo put on and a week later found the crack.