1991 MITSUBISHI MONTERO radiator cap

article, see appropriate HEATER SYSTEM article in the AIR
CONDITIONING & HEAT Section.
A/C SWITCH
Removal & Installation (Colt Vista)
From back side of control panel, push right control panel
clip right while pushing control panel out of dash panel. Allow
control panel to hang. Remove side bracket. Press temperature switch
control assembly left, and then remove A/C switch. To install, reverse
removal procedure.
Removal & Installation (Montero)
Remove lap heater duct. Remove glove box stoppers and glove
box. Remove heater control knobs. Remove center panel screw hole
plugs, and remove screws. Remove center panel. Disconnect center panel
wiring harness. Remove A/C switch. To install, reverse removal
procedure.
Removal & Installation (Pickup & Ram-50)
Remove heater control knobs. Remove glove box. Remove center
panel mounting screws. Use a trim stick to remove upper side of panel.
Remove A/C switch assembly mounting screws. Pull switch assembly
toward vehicle interior. Remove switch. To install, reverse removal
procedure.
COMPRESSOR
Removal & Installation (Colt Vista)
Discharge A/C system using approved refrigerant
recovery/recycling equipment. Disconnect high tension cable from
ignition coil. Remove distributor cap. Loosen idler pulley adjusting
bolt, and remove belt. Disconnect compressor electrical connector.
Remove high and low pressure lines and "O" rings from compressor.
Remove compressor mounting bolts. Remove compressor. To install,
reverse removal procedure.
Removal & Installation (Montero, Pickup & Ram-50)
DischargeA/C system using approved refrigerant
recovery/recycling equipment. Loosen idler pulley, and remove belt.
Disconnect compressor electrical connector. Disconnect high and low
pressure lines from compressor. Remove compressor mounting bolts.
Remove compressor. To install, reverse removal procedure.
CONDENSER
Removal & Installation (Colt Vista)
Discharge A/C system using approved refrigerant
recovery/recycling equipment. Remove front grille and grille brackets.
Remove front end cover and condenser harness. Disconnect electrical
fan connector. Slowly disconnect pressure lines from condenser. Remove
2 condenser mounting bolts. Lift up and remove condenser from vehicle.
To install, reverse removal procedure.
Removal & Installation (Montero)
Discharge A/C system using approved refrigerant
recovery/recycling equipment. Remove radiator grille. Slowly
disconnect pressure lines from condenser. Disconnect condenser fan
motor connector. Remove condenser fan mounting bolts and motor. Remove
condenser mounting bolts. Remove condenser from vehicle. To install,
reverse removal procedure.
Removal & Installation (Pickup & Ram-50)

FUEL TANKS
GAS CAPS
GASKETS
GROMMETS (VALVE COVER)
HARMONIC DAMPERS
HEATER CONTROL VALVES
HEATER CORES
HOSE AND TUBE COUPLERS, CONNECTORS AND CLAMPS
HOSE CLAMPS
HOSE CONNECTORS
HOSE COUPLERS
HOSES AND TUBES (FUEL LINES, RADIATOR, VACUUM, BY PASS,
HEATER, RECOVERY TANK AND OIL COOLERS)
HOUSINGS
IDLE AIR CONTROLS
IDLE SPEED CONTROL ACTUATORS
IGNITION BOOTS
IGNITION COIL TOWERS
IGNITION COILS
IGNITION CONTROL MODULES (ICM)
IGNITION SWITCHES
IGNITION TERMINALS
IGNITION WIRES, BOOTS, COIL TOWERS AND TERMINALS (SECONDARY)
IN-TANK FUEL STRAINERS
INERTIA FUEL SHUT-OFF SWITCHES
INTAKE AIR TEMPERATURE SENSORS
INTAKE MANIFOLDS
INTERCOOLERS
KNOCK SENSORS
LIQUID VAPOR SEPARATORS
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSORS
MASS AIR FLOW (MAF) SENSORS
METAL AIR MANIFOLDS AND PIPES
METAL AIR PIPES
MIX CONTROL SOLENOIDS
MOTOR MOUNTS
O-RINGS, GASKETS, SEALS AND SPRING LOCKS
O2 SENSORS
OIL PRESSURE SENDING UNITS
OIL PUMP PICK-UP SCREENS
OIL PUMPS
PARK NEUTRAL POSITION SWITCHES
PCV BREATHER ELEMENTS
PCV ORIFICES
PCV VALVES
PICK-UP ASSEMBLIES (INCLUDES MAGNETIC, HALL EFFECT AND
OPTICAL)
POWER STEERING PRESSURE SENSORS
POWERTRAIN CONTROL MODULES (PCM) AND PROM
POWERTRAIN CONTROL PROM
PRESSURIZED EXPANSION TANK CAPS
RADIATOR CAPS AND PRESSURIZED EXPANSION TANK CAPS
RADIATOR FAN BLADES
RADIATOR FAN CLUTCHES
RADIATORS
ROLL OVER VALVES
SEALING COMPOUNDS
SEALS
SECONDARY AIR INJECTION SYSTEM MANAGEMENT DEVICES
SENSORS AND ACTUATORS
SHROUDS, BAFFLES AND DEFLECTORS
SPARK PLUGS
SPRING LOCKS

Terminal burned, affecting
performance ............ A ........... (2) Require repair or
replacement.
Terminal burned, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal corroded,
affecting performance .. A .. Require repair or replacement.
Terminal corroded, not
affecting performance .. 2 .. Suggest repair or replacement.
Terminal loose, affecting
performance ............ B .. Require repair or replacement.
Terminal loose, not
affecting performance .. 1 .. Suggest repair or replacement.
Threads damaged ......... A .. Require repair or replacement.
Threads stripped (threads
missing) ............... A ............ Require replacement.
Wire lead conductors
exposed ................ B .. Require repair or replacement.
Wire lead corroded ...... A .. Require repair or replacement.
Wire lead open .......... A .. Require repair or replacement.
Wire lead shorted ....... A .. Require repair or replacement.
( 1) - Refer to manufacturer's diagnostic trouble code
procedure and require repair or replacement of affected
component(s).
( 2) - Determine cause and correct prior to repair or
replacement of part.
( 3) - Determine source of contamination, such as engine coolant,
fuel, metal particles, or water. Require repair or
replacement.
( 4) - Includes inoperative, intermittent operation, failure to
perform all functions, or out of OEM specification.









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POWERTRAIN CONTROL PROM
See POWERTRAIN CONTROL MODULES (PCM) AND PROM .
PRESSURIZED EXPANSION TANK CAPS
See RADIATOR CAPS AND PRESSURIZED EXPANSION TANK CAPS .
RADIATOR CAPS AND PRESSURIZED EXPANSION TANK CAPS
RADIATOR CAP AND PRESSURIZED EXPANSION TANK CAP INSPECTION








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Condition Code Procedure
Application incorrect ... B ........... Require replacement.
Coolant recovery check
valve inoperative ...... A ....... ( 1) Require replacement.
Fails to maintain proper
pressure ............... B ........... Require replacement.
Gasket missing .......... C . Require replacement of gasket.
Missing ................. C ........... Require replacement.
Seal missing ............ C ... Require replacement of seal.
( 1) - Inoperative includes intermittent operation or out of
OEM specification.









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RADIATOR FAN BLADES

1 - 20 Amp (Yellow)
Hazard Light, Dome Light, Clock
2 - 10 Amp (Red)
Taillights
3 - 10 Amp (Red)
Turn Signal Lights
4 - 10 Amp (Red)
Back-Up Lights, Gauges
5 - 15 Amp (Light Blue)
Defogger
6 - 20 Amp (Yellow)
Heater
7 - 15 Amp (Light Blue)
Stoplights
8 - 15 Amp (Light Blue)
Horn, Wiper, Washer
9 - 10 Amp (Red)
Rear Wiper, Rear Washer
10 - 15 Amp (Light Blue)
Cigarette Lighter, Radio
CAUTIONS & WARNINGS
RADIATOR FAN & CAP
DO NOT loosen or remove radiator cap when cooling system is
hot. The system is under high pressure, and hot steam or boiling
liquid could gush out if cap is loosened or removed while system is
hot.
BRAKE FLUID
Be careful when handling brake fluid as it is harmful to eyes
and may damage painted surfaces.
REPLACING BLOWN FUSE
Before replacing a blown fuse, remove ignition key, turn off
all lights and accessories to avoid damaging the electrical system. Be
sure to use fuse with the correct indicated amperage rating. The use
of an incorrect amperage rating fuse may result in a dangerous
electrical system overload.

GEN ER AL C O OLIN G S YSTE M S ER VIC IN G

1991 M it s u bis h i M onte ro
GENERAL INFORMATION
General Cooling System Servicing
* PLEASE READ THIS FIRST *
The following article is for general information only.
Information may not apply to all years, makes and models. See specific
article in the ENGINE COOLING section.
DESCRIPTION
The basic liquid cooling system consists of a radiator, water
pump, thermostat, electric or belt-driven cooling fan, pressure cap,
heater, and various connecting hoses and cooling passages in the block
and cylinder head.
MAINTENANCE
DRAINING
Remove radiator cap and open heater control valve to maximum
heat position. Open drain cocks or remove plugs in bottom of radiator
and engine block. In-line engines usually have one plug or drain cock,
while "V" type engines will have 2, one in each bank of cylinders.
CLEANING
A good cleaning compound removes most rust and scale. Follow
manufacturer's instructions in the use of cleaner. If considerable
rust and scale has to be removed, cooling system should be flushed.
Clean radiator air passages with compressed air.
FLUSHING
CAUTION: Some manufacturers use an aluminum and plastic radiator.
Flushing solution must be compatible with aluminum.
Back Flushing
Back flushing is an effective means of removing cooling
system rust and scale. The radiator, engine and heater core should be
flushed separately.
Radiator
To flush radiator, connect flushing gun to water outlet of
radiator and disconnect water inlet hose. To prevent flooding engine,
use a hose connected to radiator inlet. Use air in short bursts to
prevent damage to radiator. Continue flushing until water runs clear.
Engine
To flush engine, remove thermostat and replace housing.
Connect flushing gun to water outlet of engine. Flush using short air
bursts until water runs clean.
Heater Core
Flush heater core as described for radiator. Ensure heater
control valve is set to maximum heat position before flushing heater.

REFILLING
To prevent air from being trapped in engine block, engine
should be running when refilling cooling system. After system is full,
continue running engine until thermostat is open, then recheck fill
level. Do not overfill system.
TESTING
THERMOSTAT
1) Visually inspect thermostat for corrosion and proper
sealing of valve and seat. If okay, suspend thermostat and thermometer
in a 50/50 mixture of coolant and water. See Fig. 1. Do not allow
thermostat or thermometer to touch bottom of container. Heat water
until thermostat just begins to open.
2) Read temperature on thermometer. This is the initial
opening temperature and should be within specification. Continue
heating water until thermostat is fully open and note temperature.
This is the fully opened temperature. If either reading is not to
specification, replace thermostat.
Fig. 1: Testing Thermostat in Anti-Freeze/Water Solution
PRESSURE TESTING
A pressure tester is used to check both radiator cap and

complete cooling system. Test components as follows, following tool
manufacturer's instructions.
Radiator Cap
Visually inspect radiator cap, then dip cap into water and
connect to tester. Pump tester to bring pressure to upper limit of cap
specification. If cap fails to hold pressure, replace cap.
Fig. 2: Testing Radiator Pressure Cap
Cooling System
1) With engine off, wipe radiator filler neck seat clean.
Fill radiator to correct level. Attach tester to radiator and pump
until pressure is at upper level of radiator rating.
2) If pressure drops, inspect for external leaks. If no leaks
are apparent, detach tester and run engine until normal operating
temperature is reached. Reattach tester and observe. If pressure
builds up immediately, a possible leak exists from a faulty head
gasket or crack in head or block.
NOTE: Pressure may build up quickly. Release any excess pressure
or cooling system damage may result.
3) If there is no immediate pressure build up, pump tester to
within system pressure range (on radiator cap). Vibration of gauge
pointer indicates compression or combustion leak into cooling system.
Isolate leak by shorting each spark plug wire to cylinder block. Gauge
pointer should stop or decrease vibration when leaking cylinder is
shorted.

CATALYTIC CONVERTER
Continued operation of vehicle with a severe malfunction
could cause converter to overheat, resulting in possible damage to
converter and vehicle.
COOLANT (PROPYLENE-GLYCOL FORMULATIONS)
CAUTION: To avoid possible damage to vehicle use only ethylene-glycol
based coolants with a mixture ratio from 44-68% anti-freeze.
DO NOT use 100% anti-freeze as it will cause the formation
of cooling system deposits. This results in coolant
temperatures of over 300
\b F (149\bC) which can melt plastics.
100% anti-freeze has a freeze point of only -8\b F (-22\bC).
CAUTION: Propylene-Glycol Mixtures has a smaller temperature range
than Ethylene-Glycol. The temperature range (freeze-boil)
of a 50/50 Anti-Freeze/Water Mix is as follows:
Propylene-Glycol -26
\b F (-32\bC) - 257\b F (125\bC)
Ethylene-Glycol -35\b F (-37\bC) - 263\b F (128\bC)
CAUTION: Propylene-Glycol/Ethylene-Glycol Mixtures can cause the
destabilization of various corrosion inhibitors. Also
Propylene-Glycol/Ethylene-Glycol has a different specific
gravity than Ethylene-Glycol coolant, which will result in
inaccurate freeze point calculations.
ELECTROSTATIC DISCHARGE SENSITIVE (ESD) PARTS
WARNING: Many solid state electrical components can be damaged by
static electricity (ESD). Some will display a warning label,
but many will not. Discharge personal static electricity by
touching a metal ground point on the vehicle prior to
servicing any ESD sensitive component.
ENGINE OIL
CAUTION: Never use non-detergent or straight mineral oil.
FUEL SYSTEM SERVICE
WARNING: Relieve fuel system pressure prior to servicing any fuel
system component (fuel injection models).
HALOGEN BULBS
WARNING: Halogen bulbs contain pressurized gas which may explode if
overheated. DO NOT touch glass portion of bulb with bare
hands. Eye protection should be worn when handling or working
around halogen bulbs.
RADIATOR CAP
CAUTION: Always disconnect the fan motor when working near the
radiator fan. The fan is temperature controlled and could
start at any time even when the ignition key is in the OFF
position. DO NOT loosen or remove radiator cap when cooling
system is hot.
RADIATOR FAN