1990 VOLKSWAGEN CORRADO engine

A/C COMPRESSOR OIL CHECKING
Article Text (p. 7)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PM
compressor, receiver-drier and expansion valve. Clean expansion valve
screen. Flush entire system. Install new compressor and receiver-
drier. New compressors contain correct amount of oil. If installing
overhauled compressor, add 1.5 ounces of new refrigerant oil through
suction port.
PANASONIC ROTARY VANE DRAIN & REFILL
1) Before checking and adjusting oil level, operate
compressor at 1000-1500 engine RPM, and set controls at maximum
cooling and high blowing speed for about 10 minutes to return oil to
compressor.
2) Stop engine. Discharge refrigerant and remove compressor
from vehicle. See SERVICING PRECAUTIONS at the beginning of this
article. Drain oil from compressor through suction and discharge
ports. Measure amount of oil drained. If amount drained is more than
2.4 ounces, fill with same amount using new oil. If amount drained is
less than 2.4 ounces, fill with 2.4 ounces. Install compressor and
recharge.
3) If A/C components are replaced, add refrigerant oil to
system. Add 1.4 ounces if condenser is replaced. Add 2 ounces if the
evaporator is replaced. Oil does not need to be added if receiver-
drier is replaced.
SANDEN SCROLL DRAIN & REFILL
Discharge system. Remove compressor from vehicle. Drain oil
from compressor through inlet and outlet holes. Refill compressor with
2.8 ounces of oil through suction port. When replacing condenser, add
.5 ounce. When replacing evaporator, add 1.7 ounces. When replacing
other A/C components, add .5 ounce per component replaced.
SANDEN 5-CYL DRAIN & REFILL
1) Discharge system. Remove compressor belt and loosen
mounting bolts. Rotate compressor in brackets until filler plug is at
top. Clean area around filler plug and remove plug slowly. Rotate
front hub plate so notch in lobe is 110 degrees from the bottom. This
rotates ball end of top piston to align with oil fill port and allows
clearance for dipstick. See Fig. 1.
2) Insert compressor dipstick diagonally from right to left
until stop on dipstick contacts filler plug surface. Remove dipstick
and note oil fill level. Each increment on dipstick represents one
ounce of oil. Add oil if necessary to reach 3-4 ounce level.

A/C COMPRESSOR OIL CHECKING
Article Text (p. 8)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PMFig. 1: Sanden 5-Cylinder Oil Level Checking
Courtesy of Sanden International U.S.A, Inc.
SANDEN 7-CYL DRAIN & REFILL
1) Before checking and adjusting oil level, operate
compressor at engine idle speed, and set controls at maximum cooling
and high blowing speed for 20-30 minutes to return oil to compressor.
2) Stop engine. Discharge refrigerant and remove compressor
from vehicle. See SERVICING PRECAUTIONS at the beginning of this
article. Remove oil drain plug and drain oil. Measure amount of oil
drained. Install drain plug with new "O" ring.
3) If amount drained is more than 3 ounces, fill with same
amount using new oil. If amount drained is less than 3 ounces, fill
with 3 ounces. Install filler plug. Install compressor and recharge
system.
END OF ARTICLE

A/C COMPRESSOR SERVICING
Article Text
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PM
ARTICLE BEGINNING
1990 AIR CONDITIONING & HEAT
Compressor Service
* PLEASE READ THIS FIRST *
CAUTION: When discharging air conditioning system, use only approved
refrigerant recovery/recycling equipment. Make every attempt
to avoid discharging refrigerant into the atmosphere.
ISOLATING COMPRESSOR
NOTE: Only compressors with stem-type service valves can be
isolated.
1) Connect service gauge set to the compressor service valves
and open compressor valves slightly (turn in clockwise). Start engine
and operate air conditioning. Slowly turn compressor suction valve
clockwise toward closed (front-seated) position.
2) When suction pressure is reduced to zero or less, turn off
engine and compressor and quickly turn suction valve stem in to full
front-seated position. Suction pressure should be slightly above zero.
Turn discharge valve into front-seated position.
3) To check oil level, slowly open compressor crankcase plug
to relieve any remaining pressure. After oil level is corrected, cap
service gauge ports on both valves. Back-seat suction service valve to
allow refrigerant to enter compressor. Open discharge valve halfway.
4) Loosen discharge service valve cap, allowing refrigerant
pressure to force air out of compressor. Back-seat service valve and
tighten cap. Compressor is now ready for operation.
REFRIGERANT OIL
Only new, pure, moisture-free refrigerant oil should be used
in the air conditioning system. This oil is highly refined and
dehydrated to a point where moisture content is less than 10 parts per
million. The oil container must be tightly closed at all times when
not in use, or moisture will be absorbed into the refrigerant oil from
the air.
DISCHARGING SYSTEM PRECAUTIONS
CAUTION: When discharging air conditioning system, use only approved
refrigerant recovery/recycling equipment. Make every attempt
to avoid discharging refrigerant into the atmosphere.
If compressor has stem-type service valves, it can be
isolated and removed without discharging entire system. Otherwise,
discharge system completely using approved refrigerant

A/C SYSTEM GENERAL DIAGNOSTIC PROCEDURES
Article Text (p. 2)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PM
5000 ........................ 24.92 ......................... +5.0
6000 ........................ 23.92 ......................... +6.0
7000 ........................ 23.02 ......................... +6.9
8000 ........................ 22.22 ......................... +7.7
9000 ........................ 21.32 ......................... +8.6
10,000 ...................... 20.52 ......................... +9.4
(1) - Add correction shown to gauge readings.ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ PREPARATION FOR TESTING
1) Attach Low and High pressure gauges.
2) Start engine and allow to warm up.
3) Set system to "COOL" and blower to "HIGH".
4) Open car doors and hood.
5) Run engine at fast idle for 2-3 minutes.
AIR CONDITIONING SYSTEM PERFORMANCE CHECK TABLE
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄPERFORM TESTS: SHOULD BE: IF:
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄTemperature Check Temperature Check Is
* Switch to "LOW" blower.
* Close doors.
* Check outlet temperature. 35-45
ø F Too warm - Check control
lever operation, heater
water valve, cooling
system and gauge
readings.
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄVisual Check Visual Check Shows:
* Compressor Quiet, No Leaks Noisy - Check belts, oil
level, seals, gaskets,
reed valves.
* Condenser Free of Obstructions Blocked - Clean off.
Plugged - Flush or
replace.
* Receiver-Drier Dry & warm to touch Frosty - Check for
restriction, replace
desiccant.
* Sight Glass Clear or few bubbles Bubbly, foamy or streaks
- Check gauge readings.
* High Side Lines Dry & warm to touch Frosty or very hot -
Check for restriction or
overcharge.
* Low Side Lines Dry & cool to touch Frosty or warm - Check
for restriction, low
charge or bad valve.
* Expansion Valve Dry Frosty - Check for

A/C SYSTEM PRECAUTIONS
Article Text (p. 2)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PM
Compressor oil Check article, as well as, Component Oil Replacement
Quantities" chart under "A/C SYSTEM SPECS" article in this section.
USING R-12 REFRIGERANT - SAFETY PRECAUTIONS
1) Always work in a well-ventilated, clean area. Refrigerant
(R-12) is heavier than oxygen, and will displace oxygen in a confined
area. Always wear eye protection when working around air conditioning
systems and R-12. The system's high pressure can cause severe injury
to eyes and skin if a hose were to burst. R-12 evaporates quickly
when exposed to atmosphere, freezing anything it contacts.
2) Use care when handling refrigerant containers. DO NOT drop
or strike containers or expose refrigerant containers to excessive
heat. Containers must never be heated more than 125øF (52øC). Never
expose R-12 directly to open flame.
CAUTION: When R-12 is exposed to an open flame, drawn into a running
engine, or detected with a Halide (propane) leak tester,
poisonous phosgene gas is formed. Keep work areas ventilated
and avoid running engines near work area.
USING INDIVIDUAL R-12 CANS
Disposable refrigerant cans (referred to as one pound cans)
have a flat type seal or a screw type seal, and proper can tap must be
used for each type. Be sure sealing gasket on can tap is in good
condition. A proper safety can tap will prevent refrigerant from
flowing back into open can, as tap has a one-way flow control.
NOTE: Recent findings by the EPA indicate that refrigerant is
harmful to the Earth's protective Ozone layer. When
discharging refrigerant avoid allowing refrigerant to enter
the atmosphere. Refrigerant recovery system should be used
when discharging the system.
MULTI-CAN DISPENSING VALVES
A multi-can dispensing valve allows attachment of several
cans of refrigerant, and is a good substitute when a bulk container is
not available. Cans are installed onto each leg of multi-can
dispensing valve in the same manner as the individual cans, and each
leg has its own can tap.
CAN TAP INSTALLATION FLAT TYPE SEAL CANS
On cam-lock or one-piece can taps, first turn the handle
outward to the fully open position. Securely engage locking lugs over
the can flange, and lock them in place by turning cam lock or locking
nut. Screw tap assembly into adapter so sealing gasket is fully seated
against the can top. Turn tap inward to pierce the can and close the
tap. DO NOT open tap until ready to purge the service hose or dispense

A/C-HEATER SYSTEM - MANUAL
Article Text (p. 5)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PM
MICROSWITCH
Loosen microswitch mounting screw. Move microswitch so switch
is on when lever is at maximum A/C, NORM (normal), BI-LEVEL or extreme
right position, and off when lever is at VENT or HEAT position.
Tighten microswitch mounting screw. Recheck operation.
TEMPERATURE SWITCH
Move temperature lever to full cool position. Loosen
temperature switch mounting screw. Move temperature switch
counterclockwise to full stop position. Tighten temperature switch
mounting screw.
TROUBLE SHOOTING
NO COOLING
1) Ensure fan motor operates in all 4 speeds, air duct closes
off outside air and heater water valve is closed. Adjust belt tension.
2) Inspect receiver-drier pressure seal. If seal is good, go
to step 5). If seal is broken, evacuate and recharge system. If system
cools properly, testing is complete. If system does not cool, connect
pressure gauges.
3) Set engine speed at 2500 RPM. Insert thermometer in left
register and close all others. Place controls on high blower and
maximum cooling. With vehicle out of direct sunlight, close all
windows. Radiator fan should come on with system pressure at 200 psi
(14 kg/cmý).
NOTE: If system doors allow air leaks, evaporator will freeze up
and testing will not be possible.
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
lever. 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
both are low, locate leak and recharge system. If both are high,
replace expansion valve. If low side is too high and high side reads
too low, replace or rebuild compressor.
INSUFFICIENT COOLING
1) Ensure fan motor operates at all 4 speeds, air duct closes
off outside air intake and heater water valve is closed. Adjust
compressor belt tension and clean condenser.

A/C-HEATER SYSTEM - MANUAL
Article Text (p. 6)
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PM
NOTE: If system doors allow air leaks, evaporator will freeze up
and testing will not be possible.
2) Adjust engine speed to 2500 RPM. Position controls for
maximum cooling and high blower. Insert thermometer in left register
and close all other ducts. With vehicle out of sun, close all windows
and doors. Connect pressure gauges and check readings.
3) If both gauges read too high, replace expansion valve. If
both read too low, recharge system after locating leak. If both
readings are normal, go to next step. If pressure side is too high and
suction side is normal, go to step 5). If pressure side is too low and
suction side is too high, go to step 6). If pressure 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 installation in evaporator is 7" (178 mm)
long on all models.
5) If installation is correct, run system at maximum cooling
for 15 minutes. If thermometer indicates temperature below 36øF (2øC)
when compressor is turned off, or temperature is above 48
øF (9øC) with
compressor on, replace temperature switch.
6) Check condenser fins and clean or straighten. If operation
is still not correct, discharge system, using approved refrigerant
recovery/recycling equipment, until bubbles show in sight glass.
Recharge until bubbles disappear, and recheck pressures. If still
incorrect, locate leaks and tighten fittings. Discharge system using
approved refrigerant recovery/recycling equipment. Evacuate to remove
all air and recharge system.
7) Check for bubbles at sight glass. If present, repair leaks
and recharge system. If no bubbles are present, check condenser-to-
expansion valve line for kinks and repair if necessary. Feel along
line from condenser to expansion valve. 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 fan motor operates in all 4 speeds, air duct closes
off outside air and heater water valve is closed. Adjust belt tension
and clean condenser.
NOTE: If system doors allow air to leak by, evaporator will freeze
up and testing will no longer be possible.
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 under shade, close windows and doors and
connect pressure gauges. Operate system for 10 minutes.

AA - USING THIS SECTION (GENERAL HELP INFORMATION)
Article Text
1990 Volkswagen Corrado
For Volkswagen Technical Site: http://vw.belcom.ru
Copyright © 1998 Mitchell Repair Information Company, LLC
Thursday, March 23, 2000 09:41PM
ARTICLE BEGINNING
ENGINE PERFORMANCE
How To Use This Section
INTRODUCTION
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the new hyper-text capabilities built into this product
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It is the purpose of this repair information system to help
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below.
MENU CROSS-REFERENCE TABLEÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄTitle Associate Print (Book) Title:
A - ENGINE/VIN I D .................................... Introduction
B - EMISSION APPLICATION ..................... Emission Applications
C - TUNE-UP SPECS .............. Service & Adjustment Specifications
C - SPECIFICATIONS ............. Service & Adjustment Specifications
D - ADJUSTMENTS ............................. On-Vehicle Adjustments
E - THEORY/OPERATION ............................ Theory & Operation
F - BASIC TESTING ...................... Basic Diagnostic Procedures
G - TESTS W/ CODES ................................ Self-Diagnostics
H - TESTS W/O CODES .................... Trouble Shooting - No Codes
I - SYS/COMP TESTS ..................... Systems & Component Testing
J - PIN VOLTAGE CHARTS .......................... Pin Voltage Charts
K - SENSOR RANGE CHARTS .............. Sensor Operating Range Charts
L - WIRING DIAGRAMS ................................ Wiring Diagrams
M - VACUUM DIAGRAMS ................................ Vacuum Diagrams
N - REMOVE/INSTALL/OHAUL .......... Removal, Overhaul & Installation
ÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ Because of this we recommend that you read the rest of these
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The A - ENGINE/VIN I D article will help you identify the
vehicle and its systems. It will also explain the VIN code and in many
cases, show its location.