Help

truck started making a strange noise when accelerating. It sounds like metal on metal scraping and only makes noise when the boost comes up past 12lbs and increases as the boost increases. checked the turbo for play and every thing seams OK. ????

 

Check for a bad u joint somewhere, they can make alot of noise. Try and locate the noise more specific. That will help us help you.

 

Its more like a high pitch squeal, its not speed related.
If i'm on a hill and the boost comes up it makes the noise and if I let off on the throttle and the boost drops below 12 lbs it stops. wierd.

 

your turbo is loosing its bearings? when it does, it can grenade and shrapnel the motor. hopefully most of it gets caught in the ic.
you checked endplay. what about radial?

you know, up and down, and fore and aft?
good luck, that is a weird one.

 

Just a thought, but have you checked for an exhaust leak at the manifold? I hear they make a whole lot of noise. Mike Holmen had this happen, and thought his engine was on the way out. The leak would get worse as boost came up.