Please Help!!Turbo whistle from under the hood?!?!?!?

[fordguy420]

About two days ago i parked my truck and left it idleing then all of the sudden i hear what sounded like a whistling sound from under the hood!?!? At idle is whistles the if i rev it up to abt 1000 rpm it goes away but as soon as it goes to idle it makes a whistle noise again!??! when driving down the road it makes no noise at all... it also happens if i am coasting down a hill. i get no smoke, no rough idle, no lose of performance!!! im not sure what this is... any info will help alot!!!!

[Lilpooh]

Check all your CAC boots for rips, also the exhaust up-pipe flex joints and y-pipe flex joints for cracks.

[fordguy420]

thanks for the info!!! i looked at the cac boots.. they look good.. the noise is comming from the middle of the engine back by the turbo?!?!

[Lilpooh]

Then check your flex joints on the y-pipe/up-pipe. You can look for visual signs of soot on the firewall and surrounding parts. Or after the motor has cooled down, start up motor and feel with your hand for an exhaust leak. It's tight getting your hand back there.