GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

Note: An engine that is only operated for short periods between start-ups may have lifter noise that lasts for a few minutes. This is a normal condition.

1

Does the engine knock during initial start-up but last only a few seconds?

--

Go to Step 2

System OK

2

Inspect the engine oil.

Is the proper viscosity oil used in the crankcase?

--

Go to Step 4

Go to Step 3

3

Install oil of the proper viscosity for the expected seasonal temperatures.

Is the repair complete?

--

Go to Step 1

--

4

Inspect the hydraulic lifters.

Is there evidence of hydraulic lifter bleed-down?

--

Go to Step 5

Go to Step 6

5

Note: When the engine is stopped, some valves will be open. Spring pressure against the lifters will tend to bleed lifter down. Attempts to repair this should be made only if the problem is consistent.

Clean, test, and replace the lifters, as necessary.

Is the repair complete?

--

Go to Step 1

--

6

Inspect the crankshaft end clearance. Refer to Engine Mechanical Specifications.

Is the clearance more than specified value?

--

Go to Step 7

Go to Step 8

7

Replace the crankshaft thrust bearing.

Is the repair complete?

--

Go to Step 1

--

8

Inspect the front main bearing clearance. Refer to Engine Mechanical Specifications.

Is the clearance more than the specified value?

--

Go to Step 9

System OK

9

Replace the worn parts of the front main bearing.

Is the repair complete?

--

Go to Step 1

--