GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value

Yes

No

1

  1. Remove the flywheel inspection plate.
  2. Inspect the flywheel for the following:
  3. • Chipped gear teeth
    • Missing gear teeth
    • Bent flywheel

Does the flywheel have chipped or missing teeth or is bent?

--

Go to Step 2

Go to Step 3

2

  1. Replace the flywheel. Refer to Engine Replacement in Engine Mechanical.
  2. Start the engine.

Has the noise stopped?

--

System OK

Go to Step 3

3

Start the engine while listening to the starter motor turn.

Do you hear a high pitched whine during cranking (before the engine fires) but the engine cranks and fires normally?

--

Go to Step 4

Go to Step 5

4

Shim the starter motor towards the flywheel by adding short shims between the outboard starter motor mounting pad and the engine mount. Do not add more than four shims.

Has the noise stopped?

--

System OK

--

5

Start the engine while listening to the starter motor turn.

As the key is being turned, do you hear a high-pitched whine after the engine fires?

(The engine cranks and fires normally. This is often diagnosed as starter hang-in or a weak solenoid.)

--

Go to Step 6

Go to Step 7

6

Shim the starter motor away from the flywheel by adding long shims, one at a time, between the starter motor and the engine block.

(Flywheel runout makes this appear to be intermittent.)

Has the noise stopped?

--

System OK

--

7

Start the engine while listening to the starter motor turn.

Is there a loud "whoop" after the engine fires, but while the starter is still held engaged?

(It may sound like a siren if the engine is revved while the starter is engaged.)

--

Go to Step 9

Go to Step 8

8

Do you hear a "rumble", a "growl", or, in severe cases, a "knock" as the starter is coasting down to a stop after starting the engine?

--

Go to Step 9

System OK

9

Replace the starter motor. Refer to Starter Motor Replacement .

Has the noise stopped?

--

System OK

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