A/C - Updated Orifice Tube Service Procedure

File In Section: 1 - HVAC

Bulletin No.: 66-12-05

Date: August, 1996

SERVICE MANUAL UPDATE

Subject:
Section 1B - Heating, Ventilation and Air Conditioning - Updated Orifice Tube Service Procedure

Models:
1992-97 Chevrolet and GMC C/K Models with Rear Air Conditioning (RPO C69)

This bulletin updates Section 1B "Heater, Ventilation, and Air Conditioning" of the 1996 C/K Truck Service Manuals. The current Service Manual information has been updated to include location and repair procedures for the orifice tube in Suburban models equipped with rear air conditioning (RPO 069). The current manual states that the orifice tube is located in the condenser outlet tube, and can be removed by evacuating the air conditioning system and disconnecting the evaporator tube from the condenser outlet pipe. The orifice tube is then removed from the condenser outlet pipe using J 26549-E or equivalent. This information is correct for vehicles not equipped with rear air conditioning.





Vehicles equipped with rear air conditioning require a different orifice tube service procedure, as the orifice tube location is different (Figure 1). If the Service Manual CCOT System Air Conditioning Diagnosis Insufficient Cooling Chart brings the technician to orifice tube removal, the following procedure should be used:

Remove or Disconnect (Figure 1)

1. Recover refrigerant. Refer to "Refrigerant Recovery" in Section 1B.

2. The front evaporator tube from the liquid line near the junction block (Figure 1). It may be necessary to remove the air cleaner assembly on some models.

3. The 0-ring seal.

^ Cap or plug the open line.

4. Orifice tube from liquid line using J 26549-E or equivalent.

Install or Connect

1. Orifice tube into liquid line using J 26549-E or equivalent.

2. New 0-ring seal.

^ Coat new 0-ring seal with 525 viscosity refrigeration oil.

3. Evaporator tube to liquid line.

Tighten

Tighten line connection to 24 N.m (18 lb ft).

4. Charge system. Refer to "Charging" in Section 1B.

5. Check system for leaks. Refer to "Leak Testing" in Section 1B.