Technical Bulletin - A/C System

Retrofitting R-12 to R-134a



Please Note:

The information on this page was originally published in 1995 by
Volkswagen United States Inc. Volkswagen United States and Myself 
Assume No Responsibility for any Damages that might occur when 
using this Technical Bulletin. All national, state or local laws
should be followed when it comes to the handling, use and recycling
of R-12, R-134a or any other refrigerant.

Subject : A/C System, Retrofitting R-12 to R-134a

Model(s): All (except Fox)- Model Years 1985 to 1992 
    Group: 87       Number: 95-03

    Date: May 31, 1995 

Please read all sections of this Bulletin throughly before 
proceeding with retrofit!

At customers request and expense, A/C systems on the following models
may be retrofitted to use refrigerant R-134a.

Golf Cabriolet ----------------------- 1985 to 1992
Golf/Jetta --------------------------- 1985 to 1992
Scirocco ----------------------------- 1985 to 1989
Corrado ------------------------------ 1989 to 1992
Passat ------------------------------- 1990 to 1992
Quantum ------------------------------ 1985 to 1988
Vanagon ------------------------------ 1985 to 1991
EuroVan (Canada only) ---------------- 1992

NOTE: Retrofitting to refrigerant R-134a is not 
      reimbursable under warranty.

CAUTIONS

Caution! - Part numbers are for reference only. Always check with your Parts
           Department for the latest parts information.

Caution! - Always use separate refrigerant recovery, recycling and recharging
           service equipment for R-12 and R-134a systems. If the same piece of
           equipment is used for both R-12 and R-134a systems, residual traces
           of refrigerant will contaminate and damage the equipment.
           Service equipment includes recovery, recycling, recharging station,
           vacum pump, manifold gauges, etc.

Caution! - Do Not Blow compressed air and nitrogen through the compressor or 
           expansion valve. Refrigerant circuits retrofitted to us R-134a must
           not be rinsed with agent R11.

           Replacement compressors are filled with nitrogen. If gas does not
           escape when removing protective caps on suction and discharge ports,
           assume leakage and do not install compressor.

           When replacing damaged compressors, ensure existing mineral based
           refrigerants oil is drained and replaced with PAG oil.

           Always replace receiver drier if refrigerant circuit is left open.

           Due to residual amounts of mineral based refrigerant oil in systems
           retrofitted to use refrigerant R-134a, the newly installed PAG
           refrigerant oil will discolor immediately after use. This is normal
           and does not indicate a refrigerant related fault.                       

R-134a RETROFIT - SYSTEM PREPARATION

--- Review all Cautions, Warnings and A/C refrigerant system safety measures
    stated in appropriate model repair information. 
    Refer to Repair Manual, Air Conditioning, Repair Group 87.

--- Always use Underwriter's Laboratory (UL) approved refrigerant service
    equipment such as Kent Moore ACR3 or ACR4 or equivalent.

--- Before proceeding with retrofit, perform a visual inspection and functional
    test of complete A/C system; including instrument panel outlet temperature,
    air distribution, refrigerant system components, system pressure and leak
    test. Refer to Repair Manual, Air Conditioning, Repair Group 87. 
    Repair/replace parts as necessary.

--- Always refer to the most recent parts information for affected models when
    replacing damaged or defective R-12 refrigerant system parts (including
    routine replacement of O-Rings).

--- If replacement of damaged or leaking refrigerant hoses, compressors, 
    evaporators and condensers is necessary, blow compressed air (followed by
    nitrogen) through all remaining, disconnected, free flowing system
    components before assembly in order to remove moisture, impurities and
    remaining refrigerant oil.

--- If a component is replaced prior to retrofitting the system to R-134a, 
    an appropriate amount of PAG refrigerant oil must be added to the circuit.
    For oil quantities per component, refer to Oil Distribution charts
    in the Refrigerant Oil Distribution section below.

--- Replacement compressors are factory filled with R-12 compatable compressor
    oil. If compressor replacement is necessary, the factory filled compressor
    oil must be drained and replaced with appropriate quantity of PAG
    refrigerant oil;
    Identify compressor type and fill according to table in Capacity Tables -
    PAG Refrigerant Oil section below.

PARTS REQUIREMENT

ALL Models require the following parts:

--- Adapter/label kit : Part No. 357 820 794

--- PAG Refrigerant Oil:
    - Passenger Cars =  Part No. G 052 154 A2
    - Vanagon/EuroVan = Part No. G 052 100 A2

--- Receiver Drier (Refer to Chart Below)

--- Receiver Drier O-rings (Refer to Chart Below)

--- Compressor O-rings (Refer to Chart Below)
Model/ Model Year Receiver Drier Receiver Drier O-Rings Compressor O-Rings
Golf Cabriolet 85-92
171 820 191 B
803 260 749
803 260 749 A
803 260 749 B
Golf/Jetta 85-92
191 820 191 A
803 260 749
803 260 749 A
803 260 749 B
Scirocco 85-89
171 820 191 B
803 260 749
803 260 749 A
803 260 749 B
Corrado 89-92
191 820 191 A
803 260 749 A
1H0 820 749
Passat 90-92
357 820 191 D
803 260 749
803 260 749 A
803 260 749 B
Quantum 85-88
323 820 193 A
803 260 749
171 820 749
Vanagon 85-91
Up To 24 G 075000:
253 260 633 D
From 24 G 975001:
253 260 633 E 
803 260 749
253 260 749
Eurovan 92
(Canada only)
701 260 191 E
803 260 749
803 260 749 A
803 260 749 B
Caution! - Part numbers are for reference only. Always check with your Parts
           Department for the latest parts information.

RETROFIT PROCEDURE

--- Discharge and capture refrigerant R-12 using Kent Moore ACR3 or equivalent

--- Evacuate system to remove any R-12 contaminants

--- Remove refrigerant oil from compressor; depending on accessibility, use
    one of the following methods:
    - Use refrigerant oil evacuation feature of Kent Moore ACR3, ACR4 equivalent
    - Remove compressor, unscrew oil drain plug and drain refrigerant oil.

--- Identify compressor type and fill with quantity of PAG refrigerant oil 
    specified in the Capacity Tables - PAG Refrigerant Oil section below

--- Reinstall compressor (if removed)

--- Install new O-rings on compressor suction and discharge hose fittings.

--- Replace receiver drier. Use New O-Rings.

--- Identify and install correct R-134a adapters (from Kit Part No. 357 820 794)
    to high pressure and low pressure service valves.

    - Low pressure valve - 7/16" connection Part No. 357 820 797 A

    - High pressure valve - 3/8" connection Part No. 357 820 797 OR
      High pressure valve - 7/16" connection Part No. 357 820 797 B

--- Evacuate system for a minimum of 30 minutes using Kent Moore ACR4 or
    equivalent.

--- Charge system with refrigerant R-134a 
    (Refer to Refrigerant Capacity Table below)

--- Perform A/C system quality check and leak test.
    Refer to Repair Manual, Air Conditioning, Repair Group 87.

--- Install new R-134a adhesive label over original R-12 label on 
    radiator support.

CAPACITY TABLES

PAG Refrigerant Oil

--- Passenger Cars = Part No. G 052 154 A2

--- Vanagon/Euro Van = Part No. G 052 100 A2

Compressor

PAG Refrigerant Oil Capacity

York
100 cc (3.3 fl oz)
Sankyo, Sanden SD 508
100 cc (3.3 fl oz)
Sanden SD 510
100 cc (3.3 fl oz)
Sanden SD 709
135 cc (4.5 fl oz) (Pass Cars incl EuroVan)
240 cc (8 fl oz) (Vanagon)

 

REFRIGERANT R-134a

Model/ Model Year Capacity
Golf Cabriolet 85-92
800 g (28.2 oz)
Golf/Jetta/Vento 85-92
800 g (28.2 oz)
Scirocco 85-89
800 g (28.2 oz)
Corrado 89-92
800 g (28.2 oz)
Passat 90-92
1050 g (37 oz)
Quantum 85-88
1200 g (42.3 oz)
Vanagon 85-91
1350 g (47.6 oz)
Eurovan 92
(Canada only)
950 g (33.5 oz)

R-134a RETROFIT - REFRIGERANT OIL DISTRIBUTION

If replacement of defective components is necessary before retrofitting to 
R-134a, identify refrigerant circuit by compressor type and add PAG 
refrigerant oil directly to component according to the following application
charts.

CAUTION! - The following total system oil capacities are the maximum allowed
           for each compressor and refrigerant circuit combination.
           Do not exceed the total system oil capacity. Compressor damage
           and a decrease in cooling performance will result.
Refrigerant 
Circuit With
Model Compressor
Condenser
Evaporator
Receiver Drier
High Pressure
 Hose
Low Pressure
Hose
Total System
Oil Capacity
York 
10 cc 
(0.3 fl oz)
50 cc 
(1.7 fl oz)
20 cc
(0.7 fl oz)
15 cc
(0.5 fl oz)
15 cc
(0.5 fl oz)
300 cc
(10.0 fl oz)
Sanden SD 508
20 cc
(0.7 fl oz)
30 cc
(1.0 fl oz)
20 cc
(0.7 fl oz)
15 cc
(0.5 fl oz)
15 cc
(0.5 fl oz)
175 cc
(5.8 fl oz)
Sanden SDV 710
20 cc
(0.7 fl oz)
30 cc
(1.0 fl oz)
20 cc
(0.7 fl oz)
10 cc 
(0.3 fl oz)
10 cc 
(0.3 fl oz)
120 cc 
(4.0 fl oz)
Sanden SD 709
(only Passenger
Vehicles)
15 cc
(0.5 fl oz)
20 cc
(0.7 fl oz)
10 cc 
(0.3 fl oz)
10 cc 
(0.3 fl oz)
10 cc 
(0.3 fl oz)
135 cc
(4.5 fl oz)
Sanden SD 709
(only Vanagon)
0 cc
60 cc
(2.0 fl oz)
10 cc 
(0.3 fl oz)
10 cc 
(0.3 fl oz)
10 cc 
(0.3 fl oz)
240 cc 
(8.0 fl oz)
Sanden SD 709
(EuroVan with
1 evaporator)
-----
-----
-----
-----
-----
135 cc
(4.5 fl oz)

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Revised: July 2, 1998. 
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