My F350 has got a very loud high pitch whistle, at part throttle in below freezing temps. It seems to be very throttle position specific, esp. from a stop under normal acceleration. any ideas? 26000k just love to drive this thing. as a side bar, all the talk of fuel milage with the dpf regen using fuel, it could be worse. We could be filling a urea tank every week too.

 

This sounds quite normal to me, the turbo is very loud (high pitch) at certain boost pressures and the amount of strain on the engine.....

 

Does it almost sound like an air leak on the pass side? under torque only?

 

this is not a turbo sound, my kids say it hurts their ears. it is very high pitch, like a tuning fork. the noise is at any + throttle position, back off and it stops. if you really put your foot in it, it passes it (around 15psi-20 makes the noise). some f150s had alternator problems that sound like this. I just had the rad and pulley changed last week, now I'm going to look like a complainer to my service mngr.

 

If somebody was recently under the hood, check your aftercooler tubes make sure a hose isnt blown or a clamp was left loose or something.