VOLKSWAGEN CORRADO 1993 Repair Manual

A/C SYSTEM GENERAL SERVICING
Article Text (p. 3)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:48PMFig. 2: Underhood A/C Specification Labels (Typical)
Courtesy of Nissan Motor Co., U.S.A.
Other Means Of Identification
Refrigerant R-134a, when viewed through a sight glass, may
have a "milky" appearance due to the mixture of refrigerant and
lubricating oil. As the refrigerant and oil DO NOT exhibit a "clear"
sight glass on a properly charged A/C system, R-134a systems have no
sight glass.
Audi, Mercedes-Benz and Volkswagen use Green bands/labels on
condenser, refrigerant lines, receiver-drier and expansion valve.
Lexus A/C system hoses and line connectors have a groove, a White line
and "R-134a" marked on them. See Fig. 3.

A/C SYSTEM GENERAL SERVICING
Article Text (p. 4)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:48PMFig. 3: Identifying R-134a Hose & Line Connectors (Lexus)
Courtesy of Toyota Motor Sales, U.S.A., Inc.
REFRIGERANT OILS
Refrigerant R-12 based systems use mineral oil, while R-134a
systems use synthetic/Polyalkylene Glycol (PAG) oils. Using a mineral
oil based lubricant with R-134a will result in A/C compressor failure
due to lack of proper lubrication.
Use ONLY specified oil for the appropriate system and A/C
compressor. Always check the underhood A/C specification label or A/C
compressor label before adding refrigerant oil to A/C
compressor/system. See Fig. 2. The following R-134a refrigerant oils
are currently available.
Lexus
PAG Refrigerant Oil (ND-OIL 8) with 10P/10PA swashplate
(piston) compressor. Synthetic Refrigerant Oil (ND-OIL 9) with
through-vane (rotary vane) compressor.
Mercedes-Benz
PAG Refrigerant Oil (001 989 08 03).
Nissan
PAG Refrigerant Oil (KLH00-PAGR0) with rotary vane
compressor. PAG Refrigerant Oil (KLH00-PAGS0) with piston (swashplate)
compressor.
Saab
PAG Refrigerant Oil (40 74 787).
NOTE: Synthetic/PAG oils absorb moisture very rapidly, 2.3-5.6% by
weight, as compared to a mineral oil absorption rate of
.005% by weight.
SERVICE EQUIPMENT

A/C SYSTEM GENERAL SERVICING
Article Text (p. 5)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:48PM
Because R-134a is not interchangeable with R-12, separate
sets of hoses, manifold gauge set and recovery/recycling equipment are
required to service vehicles. This is necessary to avoid cross-
contaminating and damaging system.
All equipment used to service systems using R-134a must meet
SAE standard J1991. The service hoses on the manifold gauge set must
have manual (turn wheel) or automatic back-flow valves at the service
port connector ends. This will prevent refrigerant from being released
into the atmosphere.
For identification purposes, R-134a service hoses must have a
Black stripe along its length and be clearly labeled SAE J2196/R-134a.
The low pressure test hose is Blue with a Black stripe. The high
pressure test hose is Red with a Black stripe, and the center test
hose is Yellow with a Black stripe.
NOTE: Refrigerant R-12 service hoses will ONLY be labeled SAE
J2196.
R-134a manifold gauge sets can be identified by one or all of
the following:
* Labeled FOR USE WITH R-134a on set
* Labeled HFC-134 or R-134a on gauge face
* Light Blue color on gauge face
In addition, pressure/temperature scales on R-134a gauge sets
are different from R-12 manifold gauge sets.
SYSTEM SERVICE VALVES
SCHRADER-TYPE VALVES
NOTE: Although similar in construction and operation to a tire
valve, NEVER replace a Schrader-type valve with a tire valve.
Schrader valve is similar in construction and operation to a
tire valve. When a test gauge hose with built-in valve core depressor
is attached, Schrader stem is pushed inward to the open position and
allows system pressure to reach gauge.
If test hose does not have a built-in core depressor, an
adapter must be used. Never attach hose or adapter to Schrader valve
unless it is first connected to manifold gauge set.
Refrigerant R-12 Schrader-type valve cores have TV5 thread
size. Refrigerant R-134a Schrader-type valve cores use M6 (Metric)
threads. R-134a valve cores can be easily identified by use of "O"
rings and external spring. See Fig. 1.
SERVICE VALVE LOCATIONS
SERVICE VALVE LOCATIONS TABLEÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄVehicle High Low

A/C SYSTEM GENERAL SERVICING
Article Text (p. 6)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:48PM
Audi ........................ (1)(2) .............. (1)(3)
Acura ......................... (2) .................. (3)
BMW ........................... (4) .................. (5)
Chrysler, Eagle & Mitsubishi
Colt, Mirage & Summit ...... (1)(0) ................. (5)
Colt Vista & Summit Wagon .. (1)(0) .............. (1)(1)
Diamante ..................... (4) .................. (5)
Eclipse & Expo ............. (1)(0) .............. (1)(1)
Galant ..................... (1)(0) .............. (1)(1)
Montero .................... (1)(1) .............. (1)(1)
Pickup & Ram-50 ............ (1)(0) .............. (1)(1)
Precis ..................... (1)(0) .............. (1)(0)
Stealth & 3000GT
R-12 ......................... (1) .................. (1)
R-134a ....................... (1) .................. (5)
Ford Motor Co. ................ (4) .................. (5)
General Motors .............. (1)(2) .............. (1)(2)
Geo ........................... (4) .................. (5)
Honda ......................... (4) .................. (5)
Hyundai
Elantra & Scoupe ............. (4) .................. (5)
Excel & Sonata ............. (1)(0) .............. (1)(0)
Infiniti ...................... (4) .................. (5)
Isuzu ......................... (4) .................. (5)
Jaguar ........................ (4) .................. (5)
Lexus ......................... (4) .................. (5)
Mazda
B2200 & B2600i ............... (8) .................. (8)
Miata, MPV Protege & 323 ..... (4) .................. (5)
Navajo ....................... (6) .................. (7)
All Others ................... (1) .................. (1)
Mercedes-Benz ................. (4) .................. (5)
Nissan ........................ (4) .................. (5)
Porsche ....................... (8) .................. (8)
Saab .......................... (8) .................. (8)
Subaru
Impreza ...................... (1) .................. (1)
Legacy & Loyale .............. (4) .................. (5)
SVX .......................... (9) .................. (9)
Suzuki ........................ (4) .................. (5)
Toyota
Pickup & 4Runner ........... (1)(1) .............. (1)(1)
All Others ................... (4) .................. (5)
Volkswagen .................... (4) .................. (5)
Volvo
240, 940 & 960 ............... (4) .................. (5)
850 .......................... (1) .................. (5)
(1) - Information is not available from manufacturer.
(2) - On high pressure line (near top of condenser on Integra;
near receiver-drier on Legend; on receiver-drier on

A/C SYSTEM GENERAL SERVICING
Article Text (p. 7)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:48PM
Vigor). Use High-Side Adapter (J-25498).
(3) - On low pressure line (near battery on Integra; near
right rear of engine on Legend; near compressor on
Vigor).
(4) - On high pressure (discharge) hose/line.
(5) - On low pressure (suction) hose/line.
(6) - On high pressure line, between compressor and condenser.
(7) - On suction accumulator/drier.
(8) - On low and high pressure hoses, behind compressor.
(9) - On receiver/drier and low pressure hose (near
compressor).
(1)(0) - On compressor discharge hose and accumulator.
(1)(1) - On compressor discharge and suction ports.
(1)(2) - Front of condenser on right side.
(1)(3) - Towards rear of compressor.ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ REFRIGERANT RECOVERY/RECYCLING
Refrigerant recovery/recycling equipment is used to remove
refrigerant from vehicle's A/C system without polluting atmosphere. To
remove and recycle refrigerant, connect the recovery/recycling system
and follow instructions provided with the system.
The removed refrigerant is filtered, dried and stored in a
tank within the recovery/recycling system until it is ready to be
pumped back into the vehicle's A/C system. With refrigerant stored in
the recovery/recycling system, A/C system can be opened without
polluting atmosphere.
NOTE: Separate sets of hoses, gauges and refrigerant
recovery/recycling equipment MUST be used for R-12 and
R-134a based systems. DO NOT mix R-12 and R-134a
refrigerants, as their refrigerant oils and desiccants are
not compatible. On systems with R-134a refrigerant, use
Polyalkylene Glycol (PAG) wax-free refrigerant oil.
END OF ARTICLE

A/C-HEATER SYSTEM - MANUAL
Article Text
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:49PM
ARTICLE BEGINNING
1993 MANUAL A/C-HEATER SYSTEMS
Volkswagen United States, Inc.
Corrado SLC
SPECIFICATIONS
SPECIFICATIONS TABLEÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄApplication Specification
Compressor Type ........................ Sanden SD-709 7-Cyl.
Compressor Belt Tension (1)
System Oil Capacity (2) ........................ 3.9-4.4 ozs.
Refrigerant (R-134a) Capacity ................ 35.0-36.6 ozs.
System Operating Pressures
High Side ............................ 203 psi (13.8 kg/cm
ý)
Low Side ............................... 17 psi (1.1 kg/cm
ý)
(1) - Ribbed belt uses automatic belt tensioner.
(2) - Use PAG Compressor Oil (Part No. G 052 154 A2).
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄWARNING: To avoid injury from accidental air bag deployment, read and
carefully follow all SERVICE PRECAUTIONS and DISABLING &
ACTIVATING AIR BAG SYSTEM procedures.
AIR BAG SYSTEM PRECAUTIONS
SYSTEM OPERATION CHECK
Two lights pertaining to air bag system are located directly
above air bag symbol in instrument cluster. Control light is used to
indicate readiness of system. With ignition on, control light comes on
for about 5-8 seconds then goes out, while diagnosis unit in air bag
control unit performs an electronic test cycle of system.
If control light does not function as described, a fault
probably exists in system. If fault occurs while ignition is on, it
will be stored in fault memory. Warning light will then come on, and
air bag system will be switched off. If warning light comes on or
flickers while driving, air bag system should be tested.
SERVICE PRECAUTIONS
Observe these precautions when working with air bag systems:
* DO NOT use computer memory saver tool. Using computer memory
tool will keep air bag system active and may cause accidental
deployment of air bag unit.

A/C-HEATER SYSTEM - MANUAL
Article Text (p. 2)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:49PM
* Disable air bag system before servicing any air bag system or
steering column component. See DISABLING & ACTIVATING AIR BAG
SYSTEM.
* Because of critical operating requirements of system, DO NOT
attempt to service any air bag system component.
* DO NOT leave air bag parts unattended. Install parts in vehicle
immediately after obtaining.
* DO NOT use air bag components that have been dropped from height
of more than 18 inches.
* DO NOT allow chemical cleaners, oil and grease to contact vinyl
covering on air bag unit.
* DO NOT place stickers or covers on steering wheel.
* Always disable air bag system before performing electric welding
on vehicle.
* Air bag system can only be tested using Diagnostic Tester (VAG
1551) and Multimeter (US-1119). Never use test light on air bag
system.
* DO NOT expose air bag unit to temperatures greater than 194øF
(90
øC).
DISABLING & ACTIVATING AIR BAG SYSTEM
WARNING: System voltage is retained for about 20 MINUTES after system
is deactivated. Wait about 20 MINUTES after system is
disabled before servicing, as air bag may accidentally
deploy, causing personal injury.
Disabling & Activating System
To disable system, disconnect negative battery cable. Wait 20
MINUTES before working on vehicle. To activate system, reconnect
negative battery cable. Verify system is functioning properly. See
SYSTEM OPERATION CHECK.
CAUTION: When battery is disconnected, radio will go into anti-theft
protection mode. Obtain radio anti-theft protection code
from owner prior to servicing vehicle.
DESCRIPTION
The air conditioning system is a cycling clutch type.
Compressor is cycled on and off by a thermostatic switch to maintain
constant cooling rate. System components include evaporator, expansion
valve, receiver-drier, control panel and condenser. A dual-pressure
switch includes a high-pressure cut-out switch and a low-pressure cut-
out switch.
Control panel includes 3 rotary knobs over 2 push buttons.
See Fig. 1. Left knob controls the fan and increases fan speed when
turned clockwise. Center knob is the temperature control and increases
heat by turning clockwise. Right knob controls air distribution.
The 2 push buttons are ON/OFF switches controlling A/C. Left
button controls normal A/C (outside air). Right button gives maximum
A/C using recirculating air. See Fig. 1.

A/C-HEATER SYSTEM - MANUAL
Article Text (p. 3)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:49PMFig. 1: View Of A/C-Heater Control Panel (Corrado Similar)
Courtesy of Volkswagen United States, Inc.
OPERATION
SYSTEM CONTROLS
Air Distribution
Air distribution control knob directs airflow. With knob at 7
o'clock position, floor vents are open. With knob at 10 o'clock
position, defrost vents are open. At 2 o'clock position dash vents are
open. At 5 o'clock position, floor and dash vents are open.
Fan Speed Control
Fan switch increases fan speed when turned clockwise.
Temperature Control Knob
Temperature control knob increases heat by turning clockwise
and increases cooling by turning counterclockwise.
DUAL-PRESSURE SWITCH
High-Pressure Cut-Out Switch
This switch shuts compressor off if high pressure reaches
about 464 psi (32.6 kg/cmý). High-pressure cut-out switch will reset
when pressure decreases to about 348 psi (24.5 kg/cm
ý).
Low-Pressure Cut-Out Switch
This switch shuts compressor off when pressure in system is

A/C-HEATER SYSTEM - MANUAL
Article Text (p. 4)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:49PM
too low. This protects compressor if not enough refrigerant is in
system. Low-pressure cut-out switch shuts compressor off at about 29
psi (2.0 kg/cmý).
THERMOSWITCH
Thermoswitch shuts compressor off if coolant temperature is
greater than 248
øF (120øC).
ADJUSTMENTS
AIR DISTRIBUTION CONTROL
1) Move air distribution control knob to defrost position.
Connect 3-foot long control cable to footwell/defrost flap lever. Push
flap lever toward cable and secure cable sheath with retainer clip.
2) Move air distribution control knob to panel (vent)
position. Connect 2-foot long control cable to center flap lever. Push
flap lever away from cable and secure cable sheath with retainer clip.
TEMPERATURE CONTROL
Move temperature knob to full cool position. Connect
temperature control cable (Blue sheath) to temperature flap lever.
Push flap lever away from cable and secure cable sheath with retainer
clip.
TROUBLE SHOOTING
NO COOLING
1) Ensure blower fan motor operates in all 4 speeds. Ensure
air duct closes off outside air and heater water valve is closed.
Clean condenser.
2) Inspect receiver-drier pressure seal. If seal is good, go
to step 3). If seal is broken, replace seal. Evacuate and recharge
system. If system cools properly, testing is complete. If system does
not cool, connect pressure gauges.
3) Adjust engine speed to 2500 RPM. Set controls for maximum
cooling and high fan. Insert thermometer in left air duct and close
all other ducts. With vehicle in shade, close windows and doors and
connect pressure gauges. Operate system for 10 minutes.
4) If fan does not operate, replace pressure switch. Ensure
system is okay. If fan does come on, turn engine off, and check for
condenser obstructions and blocked airflow.
5) Turn air conditioner on and off with temperature control.
Ensure compressor clutch engages. Push lever to extreme right position
and back again. A click should be heard from compressor clutch. If a
click is not heard, check for voltage at clutch coil wire with switch
on. If voltage is present, replace clutch coil. If voltage is not
present, check wiring or replace thermostatic switch.
6) If compressor clutch operates, check gauge readings. If

A/C-HEATER SYSTEM - MANUAL
Article Text (p. 5)
1993 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Wednesday, March 22, 2000 08:49PM
both gauges read too low, locate leak and recharge system. If both
gauges read too high, replace expansion valve. If low side is too high
and high side is too low, replace compressor.
INSUFFICIENT COOLING
1) Ensure blower fan motor operates at all 4 speeds. Ensure
air duct closes off outside air intake and heater water valve is
closed. Clean condenser.
2) Adjust engine speed to 2500 RPM. Set controls for maximum
cooling and high fan. Insert thermometer in left air duct and close
all other ducts. With vehicle in shade, close windows and doors and
connect pressure gauges. Operate system for 10 minutes.
3) If both gauges read too high, replace expansion valve. If
both gauges read low, locate leak and recharge system. If both gauge
readings are normal, go to next step. If high side is too high and
suction side is normal, go to step 5). If high side is too low and
suction side is too high, go to step 6). If high side is normal and
suction side is too low, go to step 7).
4) Turn compressor off and observe gauges. If readings
equalize in 30 seconds, replace compressor. If readings take longer to
equalize, ensure capillary tube installed length is 13" (330 mm).
5) If capillary tube installation is correct, run system at
maximum cooling for 15 minutes. If thermometer indicates temperature
is less than 36øF (2øC) when compressor is turned off, or temperature
is greater than 48
øF (9øC) with compressor on, replace thermostatic
switch.
6) Check condenser fins and clean or straighten. If operation
is still not correct, discharge system until bubbles appear in sight
glass. Recharge system until bubbles disappear, and recheck pressures.
If operation is still incorrect, locate leaks and tighten fittings.
Discharge A/C system using approved refrigerant recovery/recycling
equipment. Evacuate system to remove all air and recharge system.
7) Check for bubbles at sight glass. If bubbles are present,
repair leaks and recharge system. If no bubbles are present, check
condenser-to-expansion valve line for kinks and repair if necessary.
Check line (from condenser to expansion valve) for restrictions by
feeling line for cold spots. If there are no cold spots, replace
expansion valve.
8) If cold spot is felt, remove and flush out lines and
condenser. Check for bubbles at sight glass. If there are no bubbles
present, replace compressor. If bubbles are present, check for leaks.
Repair and recharge system.
INTERMITTENT COOLING
1) Ensure blower fan motor operates in all 4 speeds. Ensure
air duct closes off outside air and heater water valve is closed.
Clean condenser.
2) Adjust engine speed to 2500 RPM. Set controls for maximum
cooling and high fan. Insert thermometer in left air duct and close
all other ducts. With vehicle in shade, close windows and doors and