this noise my truck is making is driving me insane. and it now drives my turbo-expert-friend insane too. he cant think of what it is either. its this boost related whirr-singing noise that follows boost. it cant really be heard at wot. so im wondering if maybe the wastegate is not fully shut and its cracked open a hair. im thinking maybe it would cause this strange and somewhat embarassing noise. any thoughts? took air filter tube off turbo and rode around for a minute. the noise was still present, just muffled by the louder turbo whistle.

thanks,

jeremy

 

Need more info. Did your truck lose some of its performance? Does the noise sound like a harmonic vibration or what?

 

More likely is your exhaust manifold is leaking.
Check for cracks or loose bolts.

 

I washed my truck at the car wash a while back an after I started the truck the manifold leaked at the ends around the flange. I could see the soap blowing out. I dont know how much it is leaking as far as a given number.
My friends truck sounded like the fan was going out and it was a 24 valve. The truck had not power. He took it to the Dealer of his choice and after a good ( quick) check they reflashed his computor. Any way after hearing him saying how bad the cummins engine was, no power , ect. I went over his house and tighten up the clamps on the innercooler, like I suggested in the first place. Live and learn Jim

 

doesnt really feel like it. then again i cant compare because its been making this noise since i bought it 2 months ago. i have tightened all boots. i havnt checked for tightness on the bolts, however, i felt no leaks when reaching around the manifold and the turbo housing. no visible soot traces either. it only does this when its under load (but not wot), and tends to follow boost.