A/C - Intermittent Thump Noise On Initial Start Up

File In Section: 1 - HVAC

Bulletin No.: 73-12-07

Date: March, 1997

Subject:
Intermittent A/C System Thump Noise On Initial Start Up from Front Passenger Side Floor Panel (Replace Accumulator)

Models:
1995-97 Buick LeSabre, Park Avenue
1995-97 Oldsmobile Eighty Eight
1996-97 Oldsmobile LSS
1997 Oldsmobile Regency
1995-97 Pontiac Bonneville
with 3.8L Engine (VINs K, 1 - RPOs L36, L67)

Condition

Some owners may comment on an A/C system thump noise. This thump noise is intermittent and can occur once during an ignition cycle. The source of the "thump" appears to be the front passenger side floor panel. This noise can only occur with the A/C system on.

Cause

The accumulator causes the thump noise due to rapid evaporation of liquid refrigerant that has collected in the desiccant bag prior to A/C start-up.

Correction

This condition may be corrected by replacing the accumulator. The specified service accumulator is specifically designed to correct this condition and should not be substituted for other accumulator issues. Refer to Section 1B of the appropriate Service Manual for replacement procedure.

Parts Information

Description P/N

Accumulator - A/C 2724961

Parts are currently available from GMSPO.

Warranty Information

For vehicles repaired under warranty, use:

Labor Operation Labor Time

D328O Use published labor
operation time.