Turbocharger Cleaning and Inspection

Completely inspect the turbocharger and all other engine components that may cause similar conditions before replacing the turbocharger.

Use the following information to diagnose problems caused by the turbocharger.

The turbocharger is serviced as a complete unit.

1. Remove the turbocharger oil return pipe bolts.
2. Remove the turbocharger oil return pipe and gasket.
Fig 1: View Of Turbocharger Oil Return Pipe, Bolts & Gasket
Courtesy of GENERAL MOTORS CORP.
3. Clean mating surfaces.
4. Inspect for damage to the compressor wheel, compared to a normal compressor wheel
Fig 2: View Of Compressor Wheel
Courtesy of GENERAL MOTORS CORP.
5. Inspect for damage to the compressor wheel, by a soft object.
Fig 3: View Of Damaged Compressor Wheel (Soft Object)
Courtesy of GENERAL MOTORS CORP.
6. Inspect for damage to the compressor wheel, by a hard object.
Fig 4: View Of Damaged Compressor Wheel (Hard Object)
Courtesy of GENERAL MOTORS CORP.
7. Inspect compressor blades for heavy rubbing.

   Ensure that the following conditions do not exist on the compressor wheel blades:

   • Cracks
   • Bends
   • Erosion of the blades
   • Broken blades
Fig 5: View Of Compressor Blades (Heavy Rubbing)
Courtesy of GENERAL MOTORS CORP.
8. Check the housing for signs of rubbing.
9. Check the compressor wheel for a build-up of dirt.
IMPORTANT:

• Carefully grasp the compressor wheel nut with your fingers and rotate the wheel in a clockwise direction. The wheel should turn freely with no signs of binding or scraping caused by housing contact.
• Rotate the turbocharger while pushing in and pulling out on the compressor wheel; the wheel should rotate freely with no contact with the housing.
• Carefully grasp the compressor wheel nut with your fingers and rotate the wheel while moving the wheel up and down. There should be no compressor wheel to the housing contact.

  AXIAL AND RADIAL PLAY IS NORMAL EVEN ON A NEW TURBOCHARGER.

  If the compressor wheel comes in contact with the housing, it will be very evident when rotating the wheel. The wheel will drag or scrape on the housing surface and visual damage will be evident on the wheel blades and the housing surface.

10. If the turbocharger does not pass any of these inspections, replace the turbocharger.
11. Measure the radial play. If the radial play exceeds 0.20 mm (0.0079 in) of movement, replace the turbocharger.
Fig 6: Measuring Turbocharger Radial Play
Courtesy of GENERAL MOTORS CORP.
12. Measure the axial play. If the axial play exceeds 0.11 mm (0.0043 in) of movement, replace the turbocharger.
Fig 7: Measuring Turbocharger Axial Play
Courtesy of GENERAL MOTORS CORP.
13. Install the turbocharger oil return pipe and new gasket.
14. Install the turbocharger oil return pipe bolts.

    Tighten:  Tighten the turbocharger oil return pipe bolts to 21 N.m (15 lb ft).

Fig 8: View Of Turbocharger Oil Return Pipe, Bolts & Gasket
Courtesy of GENERAL MOTORS CORP.
15. Clean the turbocharger inlet duct.
16. Clean the turbocharger inlet duct mating surfaces.
Fig 9: View Of Turbocharger Inlet Duct Mating Surfaces
Courtesy of GENERAL MOTORS CORP.
17. Inspect the turbocharger inlet duct for cracks.
18. Inspect the turbocharger inlet duct mating surfaces for damage.
19. Replace the turbocharger inlet duct if any damage is found.