Chevrolet Silverado / GMC Sierra. Service manual — part 455

7. Tighten the lock nut.

Tighten: Tighten nut to 22 N.m (16 lb ft).

Fig. 141: View Of Crankshaft Balancer Mark Aligned With Engine Mark
Courtesy of GENERAL MOTORS CORP.

8. Rotate the crankshaft one revolution in order to bring the number 1 cylinder to TDC of the

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

exhaust stroke.

Fig. 142: View Of Feeler Gage Between Tip Of Rocker Arm & Valve Lifter Bridge
Courtesy of GENERAL MOTORS CORP.

9. Loosen the valve adjusting screws.

10. Insert a feeler gage between the tip of the rocker arm and the valve bridge.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Fig. 143: View Of Rocker Arm Intake & Exhaust Valves 2, 3, 4, 5, 6, 7 & 8
Courtesy of GENERAL MOTORS CORP.

11. Adjust the valve clearance to 0.3 mm (0.012 in). Refer to Valve Clearance Adjustment

Specifications to determine which valves can be adjusted when the engine is at TDC.

12. Tighten the lock nut.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado

Tighten: Tighten nut to 22 N.m (16 lb ft).

13. Install the upper valve rocker arm covers. Refer to Valve Rocker Arm Cover

Replacement - Upper Left Side and Valve Rocker Arm Cover Replacement - Upper
Right Side.

14. Install the fan clutch. Refer to Fan Clutch Replacement (Diesel) .

TURBOCHARGER REPLACEMENT

Removal Procedure

1. Remove the transmission. Refer to Transmission Replacement .

2. Remove the left and right wheelhouse liners. Refer to Front Wheelhouse Liner

Replacement - Right Side (GMC) or Front Wheelhouse Liner Replacement - Right
Side (Chevrolet) and Front Wheelhouse Liner Replacement - Left Side (Chevrolet) or
Front Wheelhouse Liner Replacement - Left Side (GMC) .

NOTE:

If a turbocharger has failed, clean any turbocharger debris or
excessive oil from the charge air cooler system before installing
the new turbocharger. Failure to clean debris from the charge air
cooler system will cause severe turbocharger and engine damage
upon startup. Failure to clean excessive oil from the charge air
cooler system may cause an engine runaway condition on startup,
resulting in severe engine damage.

IMPORTANT: If a turbocharger failure is thought to be caused due to lack of oil,

the camshaft bearing should be checked. The number 4 camshaft
bearing bore feeds the turbocharger oil supply (feed) pipe. If this
camshaft bearing spins in the bore, the turbocharger will be
starved for oil. This will cause a failure of the turbocharger.
Failure to diagnosis this condition will result in repeat
turbocharger failures.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 6.6L - Cab & Chassis Sierra, Cab & Chassis Silverado, Sierra & Silverado