GM Service Manual Online
For 1990-2009 cars only

Step

Action

Values

Yes

No

1

Is there a heavy knock when the engine is hot and torque is applied?

--

Go to Step 2

System OK

2

Inspect the balancer and the pulley hub.

Is the balancer of the pulley hub broken?

--

Go to Step 3

Go to Step 4

3

Replace the broken balancer on the pulley hub.

Is the repair complete?

--

Go to Step 1

--

4

Inspect the torque converter bolts.

Are the bolts tightened to value specified?

45 N·m (33 lb ft)

Go to Step 5

Go to Step 6

5

Tighten the torque converter bolts.

Is the repair complete?

--

Go to Step 1

--

6

Inspect the accessory belts.

Are the belts too tight or nicked?

--

Go to Step 7

Go to Step 8

7

Replace and/or tension the belts to specifications, as necessary.

Is the repair complete?

--

Go to Step 1

--

8

Inspect the exhaust system.

Is the system grounded?

--

Go to Step 9

Go to Step 10

9

Reposition the system, as necessary.

Is the repair complete?

--

Go to Step 1

--

10

Inspect the flywheel.

Is the flywheel cracked?

--

Go to Step 11

Go to Step 12

11

Replace the flywheel.

Is the repair complete?

--

Go to Step 1

--

12

Inspect the main bearing clearance.

Is the clearance more than the value specified?

0.046 mm (0.0018 in)

Go to Step 13

Go to Step 14

13

Replace the main bearings as necessary.

Is the repair complete?

--

Go to Step 1

--

14

Inspect the rod bearing clearance.

Is the clearance more than the specified value?

0.070 mm (0.0028 in)

Go to Step 15

System OK

15

Replace the rod bearings as necessary.

Is the repair complete?

--

Go to Step 1

--