Can any one tell me the signs of a turbo charger starting to fail ? This is on a 95 -3500 GMC ( 6.5 )

Waste gate mechanism binds, sticks - should move easily with engine off, slight resistance from vacuum system.


Excessive end play (axial), or side-to-side play (radial) in the turbine shaft\bearings.


Check this just after shutdown, so max oil is still in bearings - remove inlet duct, wiggle shaft - blades should not touch compressor housing at any point.


If all checks ok, it's usually air filter first, then vacuum system, incl tubing, Wastegate Solenoid, and vacuum pump, for black smoke, no power.


Can also be faulty\broken wiring at connectors.


Wg shoud have 15" vacuum, for 25" vacuum on pump at idle.

When the turbo goes it sounds like hell.
Screeching and grinding and like gmctd said it will have slack in it.
I did the rebuid kit for one. 75 bucks for new brass and clips.

RonnieJoe; had his where the wastegate shaft had an oval hole worn.


The wastegate would stick and boost would not be as expected. It could have been worked over by a machine shop to put a new bushing for the shaft.