GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2002 🢒 Regal 🢒 Engine 🢒 Engine Mechanical - 3.8L 🢒 Drive Belt Rumbling Diagnosis

Diagnostic Aids

Vibration when the engine is operating may cause a body component or another part of the vehicle to produce rumbling noise.

The drive belt may have a condition that can not be seen or felt. Sometimes replacing the drive belt may be the only repair for the symptom.

If replacing the drive belt, and completing the diagnostic table, the noise is only heard when the drive belt is installed, there may be an accessory drive component failure. Varying the load on the accessory drive components may aid in identifying which accessory drive component is causing the rumbling noise.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This test is to verify that the symptom is present during diagnosing. Other vehicle components may cause a similar symptom.

    2.

  2. This test is to verify that the drive belt is causing the rumbling noise. The rumbling noise may be confused with an internal engine noise due to the similarity in the description. Remove only one drive belt at a time if the vehicle has multiple drive belts. With the drive belt removed the water pump may not be operate and the engine may overheat. Also DTCs may set when the engine is operated with the drive belt removed.

    3.

  3. Inspect the drive belt to ensure that the drive belt is not the cause of the noise. Small cracks across the ribs of the drive belt will not cause the rumbling noise. Belt separation is identified by the plys of the drive belt separating, this may be seen at the edge of the belt or felt as a lump in the belt.

    4.

  4. Small amounts of pilling is normal condition and acceptable. When the pilling is severe the drive belt does not have a smooth surface for proper operation.

Step

Action

Yes

No

Notice: Do not use belt dressing on the drive belt. Belt dressing causes the breakdown of the composition of the drive belt. Failure to follow this recommendation will damage the drive belt.

DEFINITION:

    • A low pitch tapping, knocking, or thumping noise heard at or just above idle.
    • Heard once per revolution of the drive belt or a pulley.
    • Rumbling may be caused from:
       - Pilling, the accumulation of rubber dust that forms small balls (pills) or strings in the drive belt pulley groove
       - The separation of the drive belt
       - A damaged drive belt

1

Did you review the Symptoms - Drive Belt diagnostic information and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Engine Mechanical

2

Verify that there is a rumbling noise.

Does the engine make the rumbling noise?

Go to Step 3

Go to Diagnostic Aids

3

  1. Remove the drive belt.
  2. Operate the engine for no longer than 30 to 40 seconds.

Does the rumbling noise still exist?

Go to one of the follwoing procedures:

Go to Step 4

4

Inspect the drive belt for damage, separation, or sections of missing ribs.

Did you find any of these conditions?

Go to Step 7

Go to Step 5

5

Inspect for severe pilling of more than 1/3 of the drive belt pulley grooves.

Did you find severe pilling?

Go to Step 6

Go to Step 7

6
  1. Clean the drive belt pulleys using a suitable wire brush.
  2. Install the drive belt. Refer to Drive Belt Replacement .

Did you complete the repair?

Go to Step 8

Go to Step 7

7

Install a new drive belt. Refer to Drive Belt Replacement .

Did you complete the replacement?

Go to Step 8

--

8

Run the engine in order to verify the repair.

Does the drive belt still rumble?

Go to Diagnostic Aids

System OK