DPRock

iTrader: (9)

If there is any of you that is a diesel tech I sure could use help I'm working on a 1999 Isuzu npr turbo diesel on heavy throttle there is a loud grinding whine noise let off it goes away I'm thinking something to do with the turbo system. Before that happen it would make the noise letting off the throttle now its making noise on heavy throttle. Driving me nuts sorry if I confused any of you guys

LeadfootDuramax

iTrader: (6)

I am no expert, but it sounds like the bearings in the turbo based on the info you gave. Can you moce the impeller on the turbo much? They should be pretty tight. If it moves that can be a sign the bearings are going. Sometimes they will start to make grooves in the turbo housing.

kennyxg

iTrader: (1)

Is it leaking any oil from the back of the motor? and also have you ever ran the motor with low oil level?

DPRock

iTrader: (9)

Kennyxg no oil leak from back of motor did have maybe a teaspoon of oil in the turbo hose going into the intake I'm feeling 100% its the turbo

sleepersilverado

iTrader: (1)

could you not pull the turbo off and run it NA to see if the sound is still there?

kennyxg

iTrader: (1)

Be prepared for at least one of the exhaust manifold bolts to break they are notorious for this.And the bolts are hardened steel.