Drive Belt Rumbling Diagnosis; Dri - GMC chevrolet camaro 2000 Service Manual

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Engine
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.
2. This test is to verify that the symptom is present
during diagnosing. Other vehicle components
may cause a similar symptom.
Engine Mechanical - 3.8L 6-37
3. 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. Remoye 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.
4. 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.
5. Small am9unts of pilling is normal condition and
· acceptable. When the pllling is severe the drive
belt does not have a smooth surface for
proper operation.
Drive Belt Rumbling Diagnosis
Step
Action Yes No
Notice: Refer to Belt Dressing Notice in Cautions and Notices.
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 Go to Symptoms -
perform the necessary inspections? Go to Step2 Drive Belt
2
Verify that there is a rumbling noise.
Go to
Does the engine make the rumbling noise? Go to Step 3 Diagnostic Aids
1 . Remove the drive belt.
Go to Engine Noise
3
2. Operate the engine for no longer than 30 to 40 seconds.
Diagnosis (Base
Does the rumbling noise still exist? Engine) Go to Step 4
Inspect the drive belt for damage, separation, or sections of
4
missing ribs.
Did you find any of these conditions? Go to Step 7 Go to Step 5
Inspect for severe pilling of more than 1/3 of the drive belt pulley
5
grooves.
Did you find severe pilling? Go to Step 6 Go to Step 7
1. Clean the drive belt pulleys using a suitable wire brush.
6 2. Reinstall 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.
Go to
Does the drive belt still rumble? Diagnostic Aids System OK