GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

Important: 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.

Did you complete the repair?

--

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

Important: 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.

Did you complete the repair?

--

Go to Step 1

--

6

Inspect the crankshaft end clearance.

Is the clearance more than specified value?

0.1 mm (0.0039 in)

Go to Step 7

Go to Step 8

7

Replace the crankshaft thrust bearing.

Did you complete the replacement?

--

Go to Step 1

--

8

Inspect the front main bearing clearance.

Is the clearance more than the specified range?

0.026-0.046 mm (0.001-0.0018 in)

Go to Step 9

System OK

9

Replace the worn parts of the front main bearing.

Did you complete the replacement?

--

Go to Step 1

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