Chevrolet Silverado / GMC Sierra. Service manual — part 142

Fig. 475: Exploded View Of Piston Rings
Courtesy of GENERAL MOTORS CORP.

3. Space the compression piston ring end gaps 120 degrees apart.

4. Space the oil control piston ring end gaps a minimum of 90 degrees apart.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado

CRANKSHAFT AND BEARING CLEANING AND INSPECTION

Tools Required

J 7872 Magnetic Base Dial Indicator

J 43690 Rod Bearing Clearance Checking Tool. See Special Tools.

J 45059 Angle Meter. See Special Tools.

Cleaning

Fig. 476: Crankshaft
Courtesy of GENERAL MOTORS CORP.

CAUTION: Refer to SAFETY GLASSES CAUTION .

IMPORTANT: Use care when handling the crankshaft. Avoid damage to the

crankshaft bearing surfaces.

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado

1. Clean the crankshaft in cleaning solvent. Remove all sludge or restrictions from the oil

passages.

2. Dry the crankshaft with compressed air.

Fig. 477: Crankshaft Bearings
Courtesy of GENERAL MOTORS CORP.

3. Clean the crankshaft bearings in cleaning solvent. Wipe the crankshaft bearings clean with a

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado

soft cloth, do not scratch the crankshaft bearing surfaces.

4. Dry the crankshaft bearings with compressed air.

Fig. 478: Identifying Different Crankshaft Journal Wear Patterns
Courtesy of GENERAL MOTORS CORP.

5. Inspect the crankshaft for the following:

Crankshaft journals (1) should be smooth with no evidence of scoring or damage.

Deep grooves (2)

Scratches or uneven wear (3)

Pitted surfaces (4)

Wear or damage to the thrust journal surfaces

Scoring or damage to the rear seal surface

Restrictions to the oil passages

Damage to the threaded bolt holes

2008 Chevrolet Silverado 1500

2008 ENGINE Engine Mechanical - 4.3L - Sierra & Silverado