Special Tools

J-7872 Magnetic Base Dial Indicator

For equivalent regional tools, refer to Special Tools.

1. Remove and discard the camshaft position actuator filter (1).
2. Clean the camshaft with cleaning solvent.

Warning: Refer to Cleaning Solvent Warning in the Preface section.




3. Inspect the camshaft for the following conditions:

•	Scored camshaft bearing journals (5)

•	Damaged camshaft lobes (4)

•	Damaged camshaft position sensor reluctor area (3)

•	Damaged threads (2)




4. Measure the camshaft journals using a micrometer.

If the camshaft journals are not within specifications, replace the camshaft.




5. Measure the camshaft runout using the J-7872 indicator .

5.1.	Mount the camshaft in V-blocks between the centers.

5.2.	Use the J-7872 indicator in order to measure the intermediate camshaft journal.

6. Measure the camshaft lobe lift using the J-7872 indicator .

6.1.	Lubricate the camshaft using GM P/N 12345501 (Canadian P/N 992704) or the equivalent.

6.2.	Set the camshaft on V-blocks.

6.3.	Use the J-7872 indicator in order to measure the lobe lift.

7. If the runout or lobe lift is not within specifications, replace the camshaft.




Note: Always install a NEW camshaft position actuator filter anytime the camshaft position actuator is removed or installed.

8. Install a NEW camshaft position actuator filter (1).