1991 MITSUBISHI MONTERO charging

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A/C C O M PR ESSO R O IL C HEC KIN G

1991 M it s u bis h i M onte ro
1991 GENERAL SERVICING
Compressor Refrigerant Oil Checking
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.
SERVICING PRECAUTIONS
NOTE: Recent findings by the EPA indicate that refrigerant is
harmful to the earth's protective Ozone layer. When
discharging refrigerant, DO NOT allow refrigerant to enter
the atmosphere. If available, use refrigerant
recovery/recycle systems when discharging system. Always
follow manufacturer's instructions.
DISCHARGING SYSTEM PRECAUTIONS
If compressor has stem-type service valves, it can be
isolated and removed without discharging entire system. See ISOLATING
COMPRESSOR at the beginning of this article. Otherwise, discharge
system completely before loosening any fittings.
DISCONNECTING LINES & FITTINGS TEST
After system is discharged, carefully clean area around all
fittings to be opened. Always use 2 wrenches when tightening or
loosening fittings to avoid twisting or distorting lines. Cap or plug
all openings as soon as lines are removed. DO NOT remove caps until
immediately before connections are made. This will keep entry of air

compressor. Evacuate and recharge system. Perform leak test.
HARRISON 4-CYL DRAIN & REFILL
NOTE: The Harrison compressor DOES NOT have an oil sump. It's
crucial that the compressor remains well oiled. It takes
very little time to destroy this compressor if it runs dry.
The Harrison 4-cyl compressor is charged (new) with 6 ounces
of refrigerant oil. Because compressor does not have an oil sump, it
should not have to be removed for oil measurement (it retains very
little oil). Note the following situations for checking and adding oil
to this compressor.
NO OIL LEAK; REPLACING COMPONENTS
If only the compressor is to be replaced, remove, drain oil,
measure and reinstall an equal amount of new oil. If evaporator is
being replaced, add 3 ounces of new oil. If condenser is being
replaced, add one ounce.
LOSS OF REFRIGERANT OVER EXTENDED PERIOD
When a loss of refrigerant has occurred over an extended
period of time and a component is being replaced to correct the leak,
add an appropriate amount of refrigerant oil to the component.
SIGNS OF EXCESSIVE OIL LEAKAGE
If system has lost excessive oil, remove accumulator. Drain
and measure oil. If more than 3 ounces is measured, replace the same
amount of new oil as was drained. If less than 3 ounces is measured,
add 3 ounces of new oil. Add and additional 2 ounces of new oil to
compensate for that lost by replacing the accumulator (held in
desiccant).
NOTE: If the exact oil charge is in doubt, drain and flush system.
Add a new 6-ounce charge of refrigerant oil to the system.
HARRISON V5 5-CYLINDER DRAIN & REFILL
1) If system is operable, run for several minutes to
stabilize system before performing repairs. Turn off engine. Discharge
system and remove compressor. See SERVICING PRECAUTIONS at the
beginning of this article. Remove drain plug. Drain and measure oil.
2) If more than one ounce is drained, add same amount. If
less than one ounce is drained, add 2 ounces of new refrigerant oil to
compressor.
3) If A/C components are replaced, add refrigerant oil to
system. Add one ounce if condenser is replaced. Add 3.5 ounces if
accumulator is replaced.
4) When replacing a component which has caused a large
refrigerant leak, add 3 ounces of new oil plus the required amount for
the part being replaced. Add oil directly to part being replaced if
possible. If oil can not be easily added to part, add oil to
accumulator.
NOTE: If oil drained contains metal chips or other debris, replace
receiver-drier. Flush out system before evacuating and
recharging.

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A/C C O M PR ESSO R S ER VIC IN G

1991 M it s u bis h i M onte ro
1991 GENERAL SERVICING
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
recovery/recycling equipment before loosening any fittings.
DISCONNECTING LINES & FITTINGS TEST
After system is discharged, carefully clean area around all
fittings to be opened. Always use 2 wrenches when tightening or
loosening fittings to avoid twisting or distorting lines. Cap or plug
all openings as soon as lines are removed. Do not remove caps until

Removal
1) Hold clutch plate and remove shaft nut. Using Clutch Plate
Remover (64 5 00), remove clutch plate. Using snap ring pliers, remove\
circlip and remove pulley assembly.
2) If pulley bearing is being replaced, remove circlip at
rear of pulley. Press bearing and spacer from pulley. Press in new
bearing with spacer and replace circlip.
Installation
1) Clean all surfaces. Install pulley assembly on compressor
and install circlip. Ensure clutch plate shim is in place on shaft.
Install clutch plate and nut. Tighten nut to 13-14 ft. lbs. (18-20 N.
m).
2) Using a feeler gauge, check clutch plate-to-pulley
clearance. Clearance should be .028-.051" (.7-1.3 mm). If clearance is\
not correct, remove clutch plate and replace clutch plate shim. See
Fig. 2 .
BOSCH 6-CYL SHAFT SEAL R & I
Removal & Installation
1) Remove clutch plate. Remove shaft key and circlip. Using
Seal Seat Remover/Installer (64 5 030), remove seal seat.
2) Using Seal Remover/Installer (64 5 040), remove shaft sea\
l
by turning seal slightly clockwise to disengage tangs and pull out
shaft seal. Remove "O" ring seal.
3) Coat new "O" ring seal with refrigerant oil and install.
Coat new shaft seal with refrigerant oil and install shaft seal on
Seal Remover/Installer (64 5 040). Ensure alignment of shaft seal and
shaft machine surfaces. Insert shaft seal and turn slightly
counterclockwise to secure on shaft.
4) Using sleeve from Seal Seat Remover/Installer (64 5 030),\
push seal seat into compressor and install circlip. Install shaft key
and clutch plate. Check compressor oil level before charging system.
Fig. 2: Bosch 6-Cylinder Compressor Clutch
Courtesy of BMW of North America, Inc.
CALSONIC V5 CLUTCH R & I

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A/C -H EA TE R S YSTE M - M AN UAL

1991 M it s u bis h i M onte ro
1991 MANUAL A/C-HEATER SYSTEMS
Chrysler Motors, Mitsubishi
Chrysler Motors: Colt Vista, Ram-50
Mitsubishi: Montero, Pickup
* 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.
A/C SYSTEM SPECIFICATIONS
SPECIFICATIONS TABLE








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Compressor Type
Colt Vista & Montero .................... Nippondenso 10-Cyl.
Pickup & Ram-50 ............................... Sanden Scroll
Compressor Belt Deflection
Colt Vista ............................ 11/32-7/16" (8-11 mm)
Montero ............................. 21/64-3/8" (8.5-9.5 mm)
Pickup & Ram-50 .................... 21/64-25/64" (8.5-10 mm)
Compressor Oil Capacity
Colt Vista & Montero ............................... 2.7 ozs.
Pickup & Ram-50 .................................... 5.0 ozs.
Refrigerant (R-12) Capacity
Colt Vista & Montero ................................ 32 ozs.
Pickup & Ram-50 ..................................... 30 ozs.
System Operating Pressures (1)
Colt Vista, Pickup & Ram-50
High Side .................... 130-220 psi (9.1-15.5 kg/cm
)
Low Side ........................ 20-26 psi (1.4-1.8 kg/cm)
Montero
Dual Unit
High Side .................. 142-199 psi (9.9-14.0 kg/cm
)
Low Side ...................... 16-30 psi (1.1-2.1 kg/cm)
Single Unit
High Side ................... 102-142 psi (7.1-9.9 kg/cm
)
Low Side ...................... 18-32 psi (1.3-2.2 kg/cm)
(1) - With ambient temperature at least 80
F (27C).








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DESCRIPTION
Slight variations exist among the manual A/C-heater systems
used. Either Sanden Scroll or Nippondenso 10-cylinder compressor is
used. Cycling of the compressor clutch is controlled by switches which
monitor temperatures and pressures.
Compressors will only operate within the normal operating
temperatures and pressures set for each model. An electric condenser
fan operates whenever A/C system is operating. System components used
vary depending upon model. Most systems include an A/C compressor
control unit, fan switch, evaporator, temperature sensor, high and low
(or dual) pressure switch, engine coolant temperature switch,
compressor, condenser, receiver-drier and various pipes and hoses.

service to the system in question, if the repair creates
or continues an unsafe condition.
Reasons to Suggest Repair or Replacement
1 - Part is close to the end of its useful life (just above
discard specifications, or weak; failure likely to occur
soon, etc.)
2 - To address a customer need, convenience, or request (to
stiffen ride, enhance performance, eliminate noise,
etc.)
3 - To comply with maintenance recommended by the vehicle's
Original Equipment Manufacturer (OEM)
4 - Technician's recommendation based on substantial and
informed experience
NOTE: Suggested services are always optional. When presenting
suggested repairs to the customer, you must present the
facts, allowing the customer to draw their own conclusions
and make an informed decision about how to proceed.
HEATING, VENTILATION, AND AIR CONDITIONING
SERVICE PROCEDURES REQUIRED AND SUGGESTED FOR PROPER VEHICLE
OPERATION
CAUTION: Before working on any air conditioning system, be sure
to review current local, state, federal, and EPA
regulations regarding charging, recycling, and disposal
of refrigerant.
ACCUMULATORS
ACCUMULATOR INSPECTION








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Condition Code Procedure
Attaching hardware
broken ................. A ... Require repair or replacement
of hardware.
Attaching hardware
missing ................ C .......... Require replacement of
hardware.
Attaching hardware not
functioning ............ A ... Require repair or replacement
of hardware.
Beyond vehicle
manufacturer's service
interval ............... 3 ............ Suggest replacement.
Dessicant at the end of
its useful life (saturated
with moisture) ......... 1 .. Suggest repair or replacement.
Dessicant bag
deteriorated ........... A ........ ( 1) Require replacement.
Further inspection required.
Leaking ................. A .. Require repair or replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
Tubing connection
leaking ................ A .. Require repair or replacement.

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A/C S YSTE M P R EC AU TIO NS

1991 M it s u bis h i M onte ro
AIR CONDITIONING & HEAT
A/C System Precautions
* 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.
BEFORE OPENING THE SYSTEM
Before disconnecting any lines or fittings, the system must
be completely discharged using approved refrigerant recovery/recycling
equipment.
DISCHARGING A/C SYSTEM
NOTE: Recent findings by the EPA indicate that R-11, R-12 and R-113
are harmful to the Earths' protective Ozone layer. Make every
attempt possible, to avoid discharging R-11, R-12 or R-113
into the atmosphere.
1) Remove service valve caps and install gauges. For high
side gauge hose, Adapter (D81L-19703-A) must be used to connect to
high side service valve.
2) Place open end of center hose in garage exhaust outlet or
in a well ventilated area. Slightly open low side gauge valve and let
refrigerant escape slowly without loosing refrigerant oil.
3) When system is nearly discharged, using approved
refrigerant recovery/recycling equipment, open high side gauge valve
to release any pressure trapped in compressor. Close valves
immediately after discharging to prevent entry of moisture.
DISCONNECTING LINES & FITTINGS
1) After system is discharged, using approved refrigerant
recovery/recycling equipment, carefully clean entire area around
coupling nut to prevent dirt entering system. Always use two wrenches
to avoid twisting or distorting lines and fittings (hold fitting with
one wrench while loosening coupling nut with second wrench).
2) Cap or plug all LINES and FITTINGS immediately to prevent
entry of air and moisture into system. Do not remove these caps until
connections are being made.
COMPONENT REPLACEMENT
When components are replaced, system oil level must be
adjusted. Add refrigeration oil to replacement component. See
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 125
F (52C). 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
refrigerant into the system.
On 2-piece can taps, be certain tap handle is turned fully
inward to the closed position. Check that locking base is turned to
its outer limit. Securely engage locking lugs over the can flange.
Turn entire tap assembly (without disturbing the closed setting)
downward into the locking base to pierce the can. DO NOT open tap
until ready to dispense into system.
SCREW TYPE SEAL CANS
Ensure can tap is fully closed. Screw refrigerant can into
can tap fitting until tight. This will pierce the can. Connect tap to
center hose on manifold gauge set. DO NOT open tap until ready to
dispense R-12 into system.
WARNING: DO NOT open high side hand valve while air conditioning