Chevrolet Silverado / GMC Sierra. Service manual — part 2123

Nicks or gouges in the bearing bore (3)

Damage to the bearing locating slots (4)

Fig. 39: Identifying Connecting Rod Bearing Bore
Courtesy of GENERAL MOTORS CORP.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

4. Measure the connecting rod bearing bore for an out-of-round condition. Refer to Engine

Mechanical Specifications (RPO LY5 VIN J) or Engine Mechanical Specifications
(RPO LC9 VIN 3) or Engine Mechanical Specifications (RPO LY2 VIN C) or Engine
Mechanical Specifications (RPO LH6 VIN M) or Engine Mechanical Specifications
(RPO LMG VIN 0) or Engine Mechanical Specifications (RPO LY6 VIN K) or
Engine Mechanical Specifications (RPO L76 VIN Y) or Engine Mechanical
Specifications (RPO L92 VIN 8) .

Fig. 40: Measuring Piston Pin Diameter
Courtesy of GENERAL MOTORS CORP.

5. To determine piston pin-to-connecting rod bore clearance, use a micrometer and measure

the piston pin OD.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

Fig. 41: Measuring Connecting Rod Pin Bore Inside Diameter
Courtesy of GENERAL MOTORS CORP.

6. To determine the piston pin-to-connecting rod bore clearance, use a micrometer and

measure the connecting rod pin bore (1) ID.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado

7. Subtract the piston pin OD measurement from the connecting rod pin bore ID measurement

to determine pin-to-bore clearance. Refer to Engine Mechanical Specifications (RPO
LY5 VIN J) or Engine Mechanical Specifications (RPO LC9 VIN 3) or Engine
Mechanical Specifications (RPO LY2 VIN C) or Engine Mechanical Specifications
(RPO LH6 VIN M) or Engine Mechanical Specifications (RPO LMG VIN 0) or
Engine Mechanical Specifications (RPO LY6 VIN K) or Engine Mechanical
Specifications (RPO L76 VIN Y) or Engine Mechanical Specifications (RPO L92
VIN 8) .

Fig. 42: Identifying Crankshaft Bearing Craters Or Pockets
Courtesy of GENERAL MOTORS CORP.

8. Inspect the connecting rod bearings for craters or pockets. Flattened sections on the bearing

halves indicate fatigue.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.8L, 5.3L, 6.0L, 6.2L, or 7.0L - Cab & Chassis Sierra, Cab & Chassis Silverado,

Sierra & Silverado