Serpentine Belt Chirp

87chevy29
GMC NUMBER: 87-T-96

GROUP: 6B - Engine Cooling

DATE: November, 1987

CORPORATE
NUMBER: 736014
SUBJECT: SERPENTINE BELT CHIRP

MODELS: 1987 M AND G VANS EQUIPPED WITH 4.3L (VIN CODE Z) ENGINES

FIGURE 1:

Some 1987 4.3L "M" and "G" vans equipped with serpentine belt accessory drive may exhibit a chirping sound from the engine compartment, ("Chirp" is a short duration, intermittent, high pitched sound and should not be confused with "squeal", which is continuous in nature.) The cause of this condition is likely to be paint in the pulley grooves of the serpentine belt or misalignment of the power steering pump pulley. The paint in the belt groove is a result of paint transfer from the A/C compressor pulley to the serpentine belt. To repair this condition, perform the following steps:

1. Remove the serpentine belt using procedures in section 6B, Engine Cooling of the service manual.

2. Remove all paint from the A/C compressor pulley grooves. A wire brush mounted on an electric drill can be used to perform this operation.
3. Check alignment of P/S pump pulley hub to the power steering pump shaft and correct as necessary (see Figure No. 1). The power steering pump pulley must be flush, +/- .010 inch, with the shaft for correct alignment.

4. Replace the serpentine belt with a new belt.

NOTICE: BELT DRESSING IS NOT TO BE USED ON THE SERPENTINE BELT, AS IT WILL ONLY AGGRAVATE THE CHIRP CONDITION.
Labor Operation: T7460

Labor Time: .2 Hr. Clean A/C pulley and inspect for proper belt alignment.

Add: .2 Hr. To loosen and align P/S pulley (include R and R lower shroud on "M" vans).