Hummer H3. Manual — part 391

8. Inspect the cylinder bores. Use J 8087 to measure the cylinder bore. See Special Tools.

Inspect the bores for the following conditions:

Wear

Taper

Runout

Ridging

9. Replace the cylinder sleeve if the bore is out of specification.

Fig. 409: Measuring Engine Block Flange Runout
Courtesy of GENERAL MOTORS CORP.

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

10. Inspect the oil pan rail for nicks. Use a flat file to remove an nicks.

11. Inspect the front cover attaching area for nicks. Use a flat file to remove any nicks.

12. Inspect the mating surfaces of the transmission case.

13. Use the following procedure to measure the engine block flange runout at the mounting bolt

hole bosses:

1. Temporarily install the crankshaft. Measure the crankshaft flange runout.

2. Hold a gage plate flat against the crankshaft flange.

3. Place J 8001 (dial indicator stem) on the transmission mounting bolt hole boss. Set the

indicator to zero.

4. Record the readings obtained from all of the bolt hole bosses. The measurements

should not vary more than 0.25 mm (0.010 in).

5. Recheck the crankshaft flange runout if the readings vary more than 0.25 mm (0.010

in). If the crankshaft flange runout is within the specification, replace the engine block.

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

Fig. 410: Measuring Bearing Bore Concentricity & Alignment
Courtesy of GENERAL MOTORS CORP.

14. Remove the crankshaft.

15. Re-install the crankshaft bearing caps, stiffener and bolts.

Tighten:

1. Tighten the crankshaft bearing cap bolts to 25 N.m (18 lb ft).

NOTE:

Refer to FASTENER NOTICE .

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3

2. Use J 45059 to tighten the crankshaft bearing cap bolts an additional 180 degrees. See

Special Tools.

16. Inspect the crankshaft main bearing bores. Use J 8087 to measure the bearing bore

concentricity and alignment. See Special Tools.

17. Remove the crankshaft main bearing cap stiffener and main bearing caps with bearings.

CYLINDER HONING

Fig. 411: Identifying Cylinder Bore Cross Hatch Pattern
Courtesy of GENERAL MOTORS CORP.

IMPORTANT: Perform the following inspections and reconditioning (if

necessary), with the crankshaft main bearing caps installed
and tightened to specification.

2007 Hummer H3

2007 ENGINE Engine Mechanical - 3.7L - H3