GMC chervolet camaro 1999 Service Manual page 812

Engine
Definitions
The following are symptomatic noises of the drive belt
) system:
Chirping
• A
high pitched noise that is usually heard once
per revolution of a drive belt pulley or a
drive belt.
• It is most common on cold, damp mornings.
• Verify this condition by squirting water onto the
drive. belt. The noise will momentarily stop.
Squeal
• A loud screeching noise that is caused by a
slipping drive belt {this is unusual for a multi-ribbed
drive belt).
• The noise occurs when a heavy load is applied to
the drive belt, such as an air conditioning
compressor engagement, snapping the throttle, or
slipping on a seized drive belt pulley.
Engine Mechanical - 3.8 L 6-29
Whine
A high-pitched continuous noise that may be caused
by a failed component bearing.
Faint Cycle Rumbling
A low-frequency noise heard once per revolution of
the drive belt.
Pilling
• The random accumulation of rubber dust in the
bottom of the multi-ribbed drive belt grooves.
• A small amount of pilling is normal.
• Operation of the drive belt system will not be
affected unless the buildup exceeds one third (1/3)
of the drive belt groove depth.
Multi-ribbed drive belts wear evenly with their drive
belt pulleys. Unusual wear indicates a correction
is needed.
Drive Belt Chirping
Step Action Value{s) Yes No
1
Check for misalignment of the drive belt pulleys.
-
Are any of the drive belt pulleys misaligned? Go to Step 2 Go to Step 3
2
Replace any misaligned drive belt pulleys.
-
Is the chirp still present?
Go to Step 3 System OK
3
Check for bent or cracked brackets.
Go to Go to
-
Are there any bent or crackea brackets? Go to Step 4
Steps
4
Replace any bent or cracked brackets.
-
Is the chirp still present? Go to Step 5 System OK
5
Check for any loose or missing fasteners.
-
Are there any loose or missing fasteners?
Go to Step 6 Go to Step 7
Tighten any loose fasteners and properly install any
6
missing fasteners. -
Is the chirp. still present? Go to Step 7 System OK
7
Check for a bent drive belt pulley flange.
-
Is the drive belt pulley flange bent? Go to Step 8 Go to Step 9
8
Replace the drive belt puUey flange.
-
..
Is the chirp still present? Go to Step 9 System OK
Check for severe pilling, exceeding 1/3 of the drive belt
9
groove depth.
- -
Is there severe pilling?
Go to Step 10
10
Replace the drive belt.
-
-
Is the chirp still present? System OK
Drive Belt Squeal
·step
Action
Value(s) Yes No
1
Check for an incorrect routing of the drive belt.
-
Is the drive belt routed correctly? Go to Step 3 Go to Step2
2
Refer to the drive belt routing.
-
Is there still a drive belt squeal? Go to Step 3
System OK
3
Check for a misaligned drive belt pulley.
-
Is there a drive belt pulley misaligned?
Go to Step 5 Go to Step 4
4
Check for incorrect belt length.
-
ls the belt length correct? Go to Step 6 Go to Step 5