SUBJECT: "Bump" Feel During A/C Compressor Engagement
NO: 18-20-97
GROUP: Vehicle Performance
DATE: May 30,1997
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 18-23-96, DATED AUG. 23, 1996, WHICH SHOULD BE REMOVED FROM YOUR FILES AND NOTED IN THE 1996 TECHNICAL SERVICE BULLETIN MANUAL (PUBLICATION NO. 81-69997010). NS/OS MODELS HAVE BEEN REMOVED AND ARE COVERED IN A SEPARATE TECHNICAL SERVICE BULLETIN.
MODELS:
1996 - 1997 (PL) Neon
1996 - 1997 (JA) Breeze/Stratus

NOTE: THIS BULLETIN APPLIES TO VEHICLES EQUIPPED WITH A THREE  SPEED AUTOMATIC TRANSAXLE OR FIVE SPEED MANUAL TRANSAXLE.
DISCUSSION:

Some vehicles may exhibit a periodic "bump" feel in the powertrain when the A/C is operating. It may be described by the vehicle operator as a slight miss, hesitation or surge while cruising at a steady speed on a smooth road surface.

If the vehicle operator is concerned with this "bump" condition, take them and the vehicle for a test drive. Test drive the vehicle with the A/C "ON" at a steady state speed of 60-65 MPH on a smooth road surface for 3 to 5 miles. If the "bump" is felt, turn the A/C "OFF" and test drive the vehicle at a steady state speed of 60-65 MPH on a smooth road surface for at least 3 to 5miles. If the "bump" is not felt with the A/C "OFF", the cause of the bump is cycling of the A/C compressor clutch.

If a "bump" continues to be felt with the A/C "OFF", further diagnosis will be required.

NOTE: THE A/C COMPRESSOR CLUTCH ALSO CYCLES DURING DEFROST MODE OPERATION.

The "bump" that is felt during A/C compressor engagement is a normal condition for these vehicle/powertrain combinations. The cause of the "bump" should be explained to the vehicle operator to assure them there is nothing wrong with their vehicle and that durability and reliability are not affected.

NO REPAIR FOR THIS CONDITION SHOULD BE ATTEMPTED.
POLICY:  Information Only