1991 MITSUBISHI MONTERO cooling

compressor.
2) Stop engine. Discharge refrigerant and remove compressor
from vehicle. See SERVICING PRECAUTIONS at the beginning of this
article. Drain compressor oil from compressor discharge port and
measure oil amount. Oil may be hard to drain if compressor is cool.
Drain oil while compressor is warm.
3) If amount drained is less than 3.2 ounces, conduct leak
tests at system connections. Repair or replace faulty parts as
necessary. Check purity of oil and oil level as follows.
4) If amount drained is more than 3.2 ounces, oil level is
okay; fill with same amount drained using new oil. If amount drained
is less than 3.2 ounces, pour in 3.2 ounces of new refrigerant oil.
DIESEL KIKI ROTARY VANE DRAIN & REFILL
1) Before checking and adjusting oil level, operate
compressor at engine idling speed, with controls set for maximum
cooling and high blower speed, for 20 to 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. Drain compressor oil from compressor discharge port and
measure the amount. Oil is sometimes hard to drain when compressor is
cool. Remove oil while compressor is warm.
3) If the amount is less than 2.4 ounces, conduct leak tests
at system connections, and if necessary, repair or replace faulty
parts. Check purity of oil and adjust oil level as follows.
4) If amount drained was above 2.4 ounces, oil level is
right. Pour in same amount as was drained. If amount drained was below
2.4 ounces, pour in 2.4 ounces of new refrigerant oil.
DIESEL KIKI 6-CYL DRAIN & REFILL
1) Before checking and adjusting oil level, operate
compressor at engine idling speed, with controls set for maximum
cooling and high blower speed, for 20 to 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 was more than 2 ounces (4.4 ounces for
Infinity), refill with same amount of new oil. If amount drained was
less than 2 ounces (4.4 ounces for Infinity), refill with 2 ounces (4\
.
4 ounces for Infinity). Install filler plug and recharge system.
FORD FX-15 6-CYLINDER DRAIN & REFILL
NOTE: Replacement FX-15 compressors contain 7 ounces of refrigerant
oil. Prior to installing compressor, drain refrigerant oil
and determine proper amount of refrigerant oil to be added.
1) Slowly discharge system. Remove A/C compressor. Drain
compressor oil from suction and discharge ports. Measure amount
drained and discard oil.
2) If amount drained from removed (old) compressor is betwee\
n
3 and 5 ounces, add drained amount of new SUNINSO 5GS refrigerant oil
into the NEW compressor through suction port.
3) If amount drained is less than 3 ounces, add 3 ounces to
the NEW compressor. If amount drained is more than 5 ounces, add
5 ounces. Use new "O" rings on refrigerant lines. Install A/C

HITACHI 5-CYL 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 port. Measure
amount of oil drained.
3) 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.
4) If A/C components are replaced. add refrigerant oil to
system. Add 1.7 ounces if condenser is replaced. Add 2.4 ounces if
evaporator is replaced. oil does not need to be added if receiver-
drier is replaced.
HITACHI 6-CYL DRAIN & REFILL
1) Before checking and adjusting oil level, operate
compressor at engine idling speed, with controls set for maximum
cooling and high blower speed, for 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 suction port. Measure amount of oil
drained. If amount drained was more than 2.4 ounces, refill with same
amount of new oil. If amount drained was less than 2.4 ounces, refill
with 2.4 ounces. Install compressor and recharge.
MATSUSHITA ROTARY VANE DRAIN & REFILL
Discharge system. Remove compressor from vehicle. Drain oil
from compressor through inlet and outlet holes. Refill compressor with
3.4-4.7 ounces of oil through suction port. When replacing evaporator,
add 2 ounces. When replacing other A/C components, add 1.4 ounces per
component replaced.
NIPPONDENSO ROTARY VANE 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. Drain compressor oil through compressor intake and discharge
ports. Measure amount drained. Oil may be hard to drain if compressor
cool. Drain compressor while compressor is warm.
3) If amount drained is less than 2.4 ounces, conduct leak
tests at system connections. If necessary, repair or replace faulty
parts. Check purity of oil level and adjust oil level as follows.
4) If amount drained is more than 2.4 ounces, oil level is
okay; fill with same amount drained using new oil. If amount drained
is less than 2.4 ounces, pour 2.4 ounces of new refrigerant oil.
5) When replacing condenser, add one ounce. when replacing
other A/C components, add .33 ounce per container replaced.
NIPPONDENSO 6 & 10-CYL DRAIN & REFILL

When inspecting system for oil loss, look for signs of
leaking (shiny, wet spots on components or underside of hood). If oil
leak is noted or component replacement is required, use the following
procedure as indicated:
NO OIL LEAK
Discharge system and change components as necessary. See
SERVICING PRECAUTIONS at the beginning of this article. Add
refrigerant oil to components as necessary.
OIL LEAK
1) Slowly discharge system. Repair or replace faulty
components. If equipped with a drain plug, remove plug, drain and
discard oil. If not equipped with a drain plug, remove compressor from
vehicle and pour oil out suction and discharge ports.
2) Replace drain plug (if equipped). Add 1.5 ounces of new
refrigerant oil through suction port. Use new gaskets or "O" rings
when replacing suction and discharge lines.
COMPRESSOR FAILURE OR SYSTEM CONTAMINATED
If either situation exists, discharge system and remove
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.
Fig. 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.

OPERATION
A/C SWITCH
The A/C switch is located in the lower, center section of
control panel. See Fig. 1. When switch is pushed, air conditioning
will operate if blower motor control lever is in a position other than
OFF.
When activated, the A/C button/switch allows the A/C
compressor clutch to engage and operate the compressor. On some
models, a light on the button will glow when button/switch is
activated.
Fig. 1: A/C Switch & Control Panel
Courtesy of Mitsubishi Motor Sales of America.
AIR SELECTOR LEVER
The air selector lever is located in the upper, left corner
of control panel and moves horizontally to select the source of air
needed inside of passenger compartment. Lever moves from OFF position
on the left to the outside air mode, to the mixture of both outside
and inside air mode, and to the recirculation mode on the right. Lever
should normally be set in the recirculation mode for maximum A/C
cooling.
BLOWER MOTOR CONTROL LEVER
Blower motor control lever is located on the lower, left
corner of control panel and moves horizontally to select blower motor
speeds. As lever is moved from far left or OFF position, increasing

speeds of blower operation are selected. In order for A/C system to
operate, blower motor control lever MUST be in a position other than
OFF.
MODE SELECTOR LEVER
Mode selector lever is located in upper right corner of
control panel. Either 2 or 6 modes are available to achieve desired
distribution of air from various outlets.
On all models, air is directed to windshield and side
windows and comes out from the panel outlets when mode selector lever
is positioned to the far left. When lever is moved one detent to the
right, air is directed to windshield and side windows simultaneously.
On 6-mode models, air is directed to floor area, windshield,
and side windows when lever is moved 2 detents to the right. When
lever is moved 3 detents to the right, air is directed to floor area.
When lever is moved to the second to last detent on control panel, air
is directed to floor area and panel outlets. When lever is in the far
right position, air will be directed to panel outlets only.
TEMPERATURE CONTROL LEVER
The temperature control lever operates blend-air door in the
heater/air conditioning unit, mixing cooled and heated air so the
selected air temperature can be obtained. The system will provide
cooled air when A/C switch is in ON position and blower motor is in
any position other than OFF. The temperature control lever should be
in the far left (maximum cooling) side of temperature selection scale
when maximum A/C cooling is desired.
DUAL PRESSURE SWITCH
The dual pressure switch, located in the refrigerant line
near condenser, is wired in series with compressor clutch. Whenever
system pressures drop below or increase above the control point of the
switch, power supplied to compressor will be cut and compressor
activity will cease until pressures are back to within operating
ranges.
ENGINE COOLANT TEMPERATURE SWITCH
The engine coolant temperature switch, located on thermostat
housing, is wired in series with compressor clutch. When coolant
temperature is greater than switch control temperature, power to
compressor is cut and compressor is turned off until temperature
returns to operating range.
EVAPORATOR THERMISTOR
The evaporator thermistor, attached to evaporator fins, is
wired in series with compressor clutch and prevents evaporator
freezing. Power to compressor clutch is cut if control temperature is
exceeded, allowing evaporator to thaw. When temperature returns to
operating range, thermistor allows power to compressor clutch.
FUSIBLE PLUG
A fusible plug, located on receiver-drier, melts and allows
refrigerant to escape when ambient temperatures in engine compartment
reach 221
F (105C). Once fusible plug has blown, it cannot be reused
and must be replaced.

Check blower switch and relay. Check A/C compressor clutch coil.
2) Ensure system is properly charged with correct amount of
refrigerant. Add refrigerant or evacuate and recharge system as
necessary. Ensure receiver-drier is not clogged. Check compressor belt
for proper tension. Check for clogged expansion valve. Check
compressor operation. Repair or replace compressor as necessary.
INSUFFICIENT AIRFLOW
Check for air leakage at air duct joint. Check for frost on
evaporator. Ensure blower motor is operating properly. Check for
obstructed air intake.
INSUFFICIENT COOLING
Ensure system is properly charged with correct amount of
refrigerant and free of air and moisture. Add refrigerant or evacuate
and recharge system as necessary. Ensure receiver-drier is not
clogged. Ensure sufficient airflow through condenser exists. Check
compressor belt for proper tension. Check compressor operation. Repair
or replace compressor as necessary. Check for clogged expansion valve.
Replace expansion valve as necessary.
INTERMITTENT COOL AIR
Check for air or moisture in system. Evacuate and recharge
system as necessary. Check for expansion valve malfunction. Replace
expansion valve if necessary. Check compressor belt for proper
tension.
TESTING
A/C SWITCH
1) Disconnect A/C switch harness connector. Using appropriate
wiring diagram as a guide, jumper appropriate terminals of A/C switch
wiring harness connector. See Fig. 4.
2) Turn blower on and momentarily turn ignition on without
starting engine. Listen for compressor clutch engagement. If
compressor clutch does not engage, check fuse and other components
wired in series with compressor clutch.
Fig. 4: A/C Switch Connector ID
Courtesy of Mitsubishi Motor Sales of America.
AIR THERMO & AIR INLET SENSORS

Fig. 7: Front Blower Switch Terminal ID (Colt Vista & Montero)
Courtesy of Mitsubishi Motor Sales of America.
DUAL PRESSURE SWITCH
Montero, Pickup & Ram-50
1) Turn engine off. Disconnect harness connector at dual
pressure switch (located near condenser). Jumper harness connector.
Turn A/C switch and blower switch to ON positions. Momentarily turn
ignition on and listen for compressor clutch engagement.
2) If compressor clutch does not engage, check evaporator
thermistor and engine coolant temperature switch. Check for a faulty
fuse. Repair or replace components as necessary. If compressor clutch
engages, go to next step.
3) Connect manifold gauge set to system, and check operating
pressures. Dual pressure switch should allow compressor operation if
system pressure is 30-384 psi (2-27 kg/cm
). If dual pressure switch
does not operate within specified pressure range, discharge system
using approved refrigerant recovery/recycling equipment, and replace
switch.
4) After replacing switch, recharge system, and monitor
pressures for proper compressor operation. If dual pressure switch
cuts power to compressor clutch while driving even though temperatures
inside have not yet decreased, high pressure side of dual pressure
switch has possibly been activated. Go to next step.
5) Discharge system using approved refrigerant
recovery/recycling equipment. Replace switch, and recharge system.
Ensure compressor clutch operates within 30-384 psi (2-27 kg/cm
).
Check for sufficient system cooling.