A/C - R-12 to R-134a Conversion Procedure: Overview
NO: 24-01-95 Rev. AGROUP: Heater & A/C
DATE: Mar. 3, 1995
SUBJECT:
R-12 to R-134a A/C Adaptation Service Procedure
THIS BULLETIN SUPERSEDES TECHNICAL SERVICE BULLETIN 24-01-95 EFFECTIVE DATE MAR. 3, 1995 WHICH SHOULD BE REMOVED FROM YOUR FILES. THIS IS A COMPLETE REVISION THAT ADDS MODELS, PARTS AND PROCEDURES.
THIS PROCEDURE SHOULD ONLY BE PERFORMED ON VEHICLES TO MAINTAIN AIR CONDITIONING OPERATION WHEN R-12 REFRIGERANT IS NO LONGER AVAILABLE. COOLING PERFORMANCE MAY BE LESS THAN ORIGINAL SYSTEM DEPENDENT ON OPERATING CONDITIONS AND ALSO MAY VARY BETWEEN VEHICLE MODELS.
MODELS:
1989 - 1993 (AA) Accaim/LeBaron Sedan/Spirit
1988 - 1994 (AB)(B) Ram Van/Wagon
1988 - 1993 (AC)(C) Dynasty/New Yorker/New Yorker Salon
1988 - 1993 (AD)(D) Ram Pickup/Ram Cab & Chassis
1989 - 1993 (AG) Daytona
1989 (AH) Lancer/LeBaron GTS
1989 - 1993 (AJ) LeBaron Coupe/LeBaron Convertible
1989 (AK) Aries/Reliant
1988 - 1990 (AL)(L) Horizon/Omni
1988 - 1989 (AM/M) Gran Fury/Diplomat/Newport/Fifth Avenue
1988 - 1993 (AN)(N) Dakota/Dakota Cab & Chassis
1989 - 1993 (AP) Shadow/Shadow Convertible/Sundance
1990 - 1991 (AQ) Chrysler's TC (Maserati Coupe)
1984 - 1992 (AS)(S) Caravan/Voyager/Town & Country
1990 - 1993 (AY) Imperial/New Yorker Fifth Avenue
1992 (ES) Chrysler Voyager (European Market)
1988 - 1992 (MJ) Comanche
1988 - 1991 (SJ) Grand Wagoneer
1988 - 1994 (XJ) Cherokee/Wagoneer
1988 - 1994 (YJ) Wrangler
NOTES:
1. This bulletin excludes (AB) vehicles built after 8/1/93 and (XJ/YJ) vehicles built after 1/1/94. These vehicles are equipped with R-134a refrigerant.
2. 1989-1991 (AD) non-intercooled diesel engine equipped vehicles are not available for adaptation.
3. 1990-1991 (AQ) vehicles equipped with 2.2L engines are not available for adaptation.
4. 1987-1992 (AS) vehicles equipped with 3.0L/3.3L engines and front and rear A/C may exhibit high system pressures and panel outlet temperature variations when operated in high ambients after being adapted to R-134a. These vehicles may require an engine cooling system upgrade package.
DISCUSSION:
This bulletin involves adapting vehicles with R-12 refrigerant A/C systems to operate using R-134a.
NOTE:
WHEN SERVICING THE AIR CONDITIONING SYSTEM, FOLLOW ALL CAUTIONS AND WARNINGS AS OUTLINED IN THE APPROPRIATE SERVICE MANUAL.
PROCEDURE:
A. INITIAL SYSTEM OPERATION AND PREPARATION
1. Review the Component Chart and installation notes attached to determine the parts required for the particular vehicle being adapted.
2. If the system is functioning properly, proceed to step A3. If the system is not functioning, determine the cause. If the system has no charge, charge the system to 50 psi with R-12 refrigerant. Identify any leaks and/or failed components. If the system is still not functioning, proceed to Step A4.
3. Operate the A/C system at engine idle speed for 15 minutes on high blower speed and outside air mode to maximize the oil in the compressor.
4. Evacuate the system using an approved recycling/recovery station.
NOTE:
WHEN REPLACING ANY COMPONENTS ANDIOR OPENING ANY LINE FITTINGS, NEW R-134a COMPATIBLE SEALS OR O-RINGS MUST BE INSTALLED.
5. Repair or replace any failed components with the exception of the compressor.
B. CONVERSION PROCEDURE
1. Remove the compressor and drain the mineral oil. Inspect oil for any unusual metal content. If a new compressor is a required adaptation part or is being replaced because it is a failed part, the mineral oil must be drained from the new compressor. In this case it will not be necessary to drain the oil from the old compressor.
NOTE:
IF THE COMPRESSOR HAS BEEN PREVIOUSLY REPLACED WITH A 709CA OR 709CC SERIES COMPRESSOR, IT WILL NOT HAVE TO BE REPLACED UNLESS IT HAS FAILED. IT CAN BE IDENTIFIED BY THE CASTING NUMBERS "709CA" OR "709CC" LOCATED ADJACENT TO THE SUCTION AND DISCHARGE PORTS.
2. With the compressor off the vehicle, refill with new R-134a refrigerant oil in the amount called out in the Adaptation Component Chart.
NOTE:
SPECIAL EFFORT MUST BE USED TO KEEP ALL R-134a SYSTEM COMPONENTS CAPPED TO PREVENT MOISTURE FROM ENTERING THE AIC SYSTEM OIL. MOISTURE IN THE OIL IS VERY DIFFICULT TO REMOVE AND WILL CAUSE A RELIABILITY PROBLEM WITH THE COMPRESSOR.
3. Remove and discard the filter/drier/accumulator.
4. Replace the HPRV (High Pressure Relief Valve) with the specified R-134a part listed in the Adaptation Component Chart. Refer to the appropriate Service Manual for location. In some applications the HPRV is located on the filter/drier. The HPRV on the new filter/drier must be replaced with the new R-134a HPRV.
5. Replace the HPCO (High Pressure Cutout switch). Refer to the appropriate Service Manual for location. For vehicles without HPCO switches, install a switch and wiring overlay in the system on the high pressure R-134a adaptor switch tee as specified in the Adaptation Component Chart. For SJ/XJ/YJ vehicles, the LPCO (Low Pressure Cutout Switch) is located on the filter/drier and must be replaced with a dual function HPCO/LPCO switch as specified in the Adaptation Component Chart.
6. Install the filter/drier or accumulator using new R-134a compatible gaskets or 0-rings.
7. Install the compressor on the vehicle using the new R-134a compatible gaskets or 0-rings.
8. Clean old R-12 service ports with a steel brush.
NOTE:
REMOVE THE SCHRADER VALVE CORE FROM ALL R-12 SERVICE PORTS EXCEPT WHEN USING STRAIGHT R-134a ADAPTERS. FAILING TO DO SO WILL PREVENT THE SYSTEM FROM BEING EVACUATED OR FILLED WITH REFRIGERANT.
9. Review the R-134a adaptor choices as identified in the Adaptation Component Chart. Refer to the R-134a Charge Port Adaptor chart and select the appropriate port adaptor which allows for sufficient clearance in the engine compartment to attach R-134a service equipment couplings and/or HPCO switches. Also check for proper clearance between the hood and the R-134a adaptor/switch.
NOTE:
CAP OFF ANY REMAINING R-12 PORTS USING SEAL CAP P/N 4773153 (3/8-24 THD.) OR P/N 4773154 (7/16-20 THD.).
10. Evacuate the system for a minimum of 45 minutes at 26 in. Hg or greater. Charge the system with R-134a with the amount called out in the Adaptation Component Chart.
NOTE:
THE A/C SYSTEM SIGHT GLASS IS NOT VALID FOR DETERMINING THE CORRECT R-134a CHARGE LEVEL ON A ADAPTED SYSTEM. THIS IS DUE TO THE RESIDUAL MINERAL OIL LEFT IN THE SYSTEM. IT IS HELD IN SUSPENSION AND DOES NOT MIX WITH R-134a REFRIGERANT. IT WILL APPEAR AS A WHITE "MILKY" STREAM OF REFRIGERANT THROUGH THE SIGHT GLASS.
11. Fill in the required blue R-134a A/C adaptation label, P/N 4762869, using a typewriter or ball-point pen. See label illustration for details. If possible, place the new label over the existing R-12 label. If the new label does not completely cover the existing label, remove the old label before installing the revised label. If the A/C information is part of a general vehicle information label, cut out only that part that pertains to the A/C system.
NOTE:
THE CLEAR MYLAR OVERLAY MUST BE INSTALLED OVER THE NEW LABEL.
12. Check system for leaks with approved R-134a equipment that meets Chrysler and SAE J1627 specifications.
C. PERFORMANCE TEST PROCEDURE
Review Safety Precautions and Warnings before proceeding with this procedure. Air temperature of the test area and inside the vehicle must be 70°F (21°C) minimum for this test.
1. Connect a tachometer and A/C manifold gauge set.
2. Set control to A/C, PANEL, and RECIRC or MAX A/C, with the temperature control at "full cool" and blower on "high".
3. Start engine and hold at 1,000 RPM with A/C clutch engaged.
4. Engine should be at normal operating temperature and all doors and windows closed.
5. Insert a thermometer in the left center A/C outlet and operate the engine for five minutes. The A/C clutch may cycle depending on ambient conditions.
6. With the A/C clutch engaged, compare the discharge air temperature to the A/C Performance Temperature chart provided.
7. If the discharge air temperature or discharge and suction pressure are not within the specified range, refer to the diagnostic procedure in the appropriate Service Manual.
POLICY: Information Only
Attachments
COMPRESSOR DRIVE BELT CHART
R-134a CHARGE PORT ADAPTER CHART
R-134a ADAPTATION LABEL
P/N 4762869
R-134a PERFORMANCE CHART
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R-134a PERFORMANCE CHART
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R-134a PERFORMANCE CHART
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R-134a PERFORMANCE CHART
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