Cleaning and Inspection

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Measuring Camshaft Lobes

Courtesy of GENERAL MOTORS CORP.

Clean the camshafts with cleaning solvent.
Inspect the camshafts for the following conditions:
- Scored camshaft journals
- Damaged camshaft lobes
- Damaged camshaft sprocket locator pin slots
- Damaged threads
Measure the camshaft lobes using a micrometer. The intake camshaft lobes should be a minimum of 41.5 mm (1.635 in). The exhaust camshaft lobes should be a minimum of 41 mm (1.615 in).

Fig 2: Measuring Camshaft Runout

Courtesy of GENERAL MOTORS CORP.

Use J 7872 to measure the camshaft runout.
1. Set the camshaft in V-blocks between the centers.
2. Measure the intermediate camshaft journal.
Use J 7872 to measure the camshaft lobe lift.
1. Lubricate the camshaft to V-block contact areas with engine oil.
2. Set the camshaft on V-blocks.
3. Measure the camshaft lobe lift.
If the runout or camshaft lobe lift is not within specifications, replace the camshaft.