A/C - Induced Knock Sound In Engine Compartment

NUMBER: 24-004-07

GROUP: Heating & A/C

DATE:May 18, 2007

SUBJECT:

A/C Induced Knock Sound in Engine Compartment

OVERVIEW:
This bulletin involves diagnosing the condition and if confirmed, replacing the NC compressor with a new design.

MODELS:

2007-2008 (JS) Avenger

2007 (JS) Sebring

2008 (JS27) Sebring Convertible

NOTE:
This information applies to models equipped with a 2.7L or 3.5L engine (Sales code EER or EGF) built through May 8, 2007.

SYMPTOM/CONDITION:

Some customers may experience a knocking sound (diesel like) heard coming from the engine compartment. This sound may only occur during off idle (800 to 1000 rpm) high ambient conditions greater than 32° C (90° F) with the A/C system in the "ON position. High head pressures may load the compressor pulley bearing in such a way to create a diesel like knock sound.

DIAGNOSIS:

Verify the condition as follows:

1. Connect a set of A/C gauges to the vehicle.

2. Run the engine to bring the engine to normal operating temperatures.

3. Switch the AC system "ON" and set the blower to low and A/C controls to full cold. Block the condenser air flow temporarily to increase under hood temperatures and raise the NC discharge temperature to greater than 2.1 MPa (305 PSI).

4. Leave the A/C "ON", low blower and A/C controls set to full cold. Engage the parking brake, place your foot on the service brake, and gently sweep the idle between 800 and 1000 RPM while listening for the diesel like knocking sound.

5. If the sound is heard, switch the AC system "OFF". Does the knocking sound go away?

a. Yes - perform the Repair Procedure.

b. No - Stop the verification, Further diagnosis will be required.





PARTS REQUIRED:





SPECIAL TOOLS/EQUIPMENT REQUIRED:

REPAIR PROCEDURE:

1. Using the procedures found in DealerCONNECT > TechCONNECT, replace the A/C compressor with pn 55111408AD

POLICY:
Reimbursable within the provisions of the warranty.





TIME ALLOWANCE:





FAILURE CODE:

Disclaimer:
This bulletin is supplied as technical information only and is not an authorization for repair.