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Mitsubishi 380. Manual - part 212

ON-VEHICLE SERVICE

HEATER, AIR CONDITIONING AND VENTILATION

55-144

REFRIGERANT LEAK INSPECTION PROCEDURE

M1552001500299

LEAK INSPECTION

1. Check for leakage using Special Tool at the following loca-

tions.

CAUTION

Good ventilation is necessary during the leak inspection. If
the surrounding air is contaminated with refrigerant gas,
the inspection readings will not be accurate.

25DB164A

ELECTRONIC LEAK DETECTOR

25DB163A

LEAK CHECK LOCATION

SUCTION HOSE TO TX VALVE

LIQUID TUBE TO TX VALVE

SUCTION HOSE JOINT

LOW PRESSURE SERVICE
VALVE

HIGH PRESSURE SERVICE
VALVE

CONDENSER-DISCHARGE
HOSE JOINT

PRESSURE SENSOR

CONDENSER-LIQUID TUBE
JOINT

COMPRESSOR-SUCTION HOSE
JOINT

10. COMPRESSOR-DISCHARGE

HOSE JOINT

11. UNDER COMPRESSOR CLUTCH
12. AROUND MODULATOR CAP
13. TX VALVE TO EVAPORATOR

JOINT

LEAK CHECK LOCATION

ON-VEHICLE SERVICE

HEATER, AIR CONDITIONING AND VENTILATION

55-145

LOST CHARGE

If the system has lost all of its refrigerant charge due to a leak:
1. Evacuate the system. (Refer to

P.55-142

2. Charge the system with approximately 0.453 kg (1 pound) of

refrigerant.

3. Check for leaks.

4. Discharge the system.

5. Repair leaks.

CAUTION

Replacement filter-dryer units must be sealed while in
storage. The dryer used in these units will saturate water
quickly upon exposure to the atmosphere. When installing
a dryer, have all tools and supplies ready for quick assem-
bly to avoid keeping the system open any longer than nec-
essary.
6. Replace receiver dryer. (Refer to

P.55-168

7. Evacuate and charge system.

LOW CHARGE

If the system has not lost all of its refrigerant charge; locate and
repair all leaks. If it is necessary to increase the system pres-
sure to find the leak (because of an especially low charge) add
refrigerant. If it is possible to repair the leak without discharging
the refrigerant system, use the procedure for correcting low
refrigerant level.

HANDLING TUBING AND FITTINGS

Kinks in the refrigerant tubing or sharp bends in the refrigerant
hose lines will greatly reduce the capacity of the entire system.
High pressures are produced in the system when it is operat-
ing. Extreme care must be exercised to make sure that all con-
nections are pressure tight. Dirt and moisture can enter the
system when it is opened for repair or replacement of lines or
components. The following precautions must be observed. The
system must be completely discharged before opening any fit-
ting of connection in the refrigeration system. Open fittings with
caution even after the system has been discharged. If any
pressure is noticed as a fitting is loosened, allow trapped pres-
sure to bleed off very slowly.
Never attempt to rebend formed lines to fit. Use the correct line
for the installation you are servicing. A good rule for the flexible
hose lines is keep the radius of all bends at least 10 times the
diameter of the hose.

AC001388

LOW-PRESSURE
VALVE

HIGH-PRESSURE
VALVE

GAUGE MANIFOLD

CHARGING
HOSE (RED)

SLEEVE

CHARGING
HOSE (BLUE)

ADAPTOR
VALVE
(FOR
LOW-PRES-
SURE)

ADAPTOR
VALVE
(FOR HIGH-
PRESSURE)

LOW-
PRESSURE
SERVICE
VALVE

HIGH-
PRESSURE
SERVICE
VALVE

ON-VEHICLE SERVICE

HEATER, AIR CONDITIONING AND VENTILATION

55-146

Sharper bends will reduce the flow of refrigerant. The flexible
hose lines should be routed so that they are at least 80 mm
(3.1 inches) from the exhaust manifold. It is good practice to
inspect all flexible hose lines at least once a year to make sure
they are in good condition and properly routed.
On standard plumbing fittings with O-rings, these O-rings are
not reusable.

AIR CONDITIONING NOISE TEST

You must first know the conditions when the noise occurs.
These conditions are: weather, vehicle speed, in gear or neu-
tral, engine temperature or any other special conditions.
Noises that develop during A/C operation can often be mislead-
ing. For example: what sounds like a failed front bearing or
connecting rod, may be caused by loose bolts, nuts, mounting
brackets, or a loose clutch assembly. Verify accessory drive
belt tension (power steering or generator).
Improper accessory drive belt tension can cause a misleading
noise when the compressor is engaged and little or no noise
when the compressor is disengaged.
Drive belts are speed-sensitive. That is, at different engine
speeds, and depending upon belt tension, belts can develop
unusual noises that are often mistaken for mechanical prob-
lems within the compressor.
Normal air conditioning operation will generate some level of
operational noise. To judge what is normal and abnormal,
requires an understanding of the air conditioning system. This
test is to detail the most common noise complaints and the
repair methods.

VEHICLE CONDITION

1. Ensure the system is not over or under charged.(Refer to

P.55-142

2. Tighten all compressor mounting bolts, clutch mounting

bolts and compressor drive belt.

3. Inspect layout of the system is correct, ie no interference

between hoses and all retaining clamps are in place.

AC001388

LOW-PRESSURE
VALVE

HIGH-PRESSURE
VALVE

GAUGE MANIFOLD

CHARGING
HOSE (RED)

SLEEVE

CHARGING
HOSE (BLUE)

ADAPTOR
VALVE
(FOR
LOW-PRES-
SURE)

ADAPTOR
VALVE
(FOR HIGH-
PRESSURE)

LOW-
PRESSURE
SERVICE
VALVE

HIGH-
PRESSURE
SERVICE
VALVE

ON-VEHICLE SERVICE

HEATER, AIR CONDITIONING AND VENTILATION

55-147

TEST PROCEDURES

1. Select a quiet area for testing.

2. Duplicate problem (customer complaint) as much as

possible.

3. Judge if the noise is abnormal (ie. it is important to

understand the characteristics of the vehicle and its normal
state to judge what is abnormal) - Compare with similar
vehicle if necessary.

4. Detail what and how noise occurs.

5. Find the noise source and verify its transmission by isolating

the subject part from the vehicle.

6. Repair the problem.

7. Explain and report your findings.

DETAILS OF A/C NOISE

POSSIBLE CAUSES, CHECKS AND REPAIRS

NOISE DESCRIPTION

WHEN IT OCCURS

SOURCE OF NOISE

Rumbling (Bearing noise)

With A/C On or Off

Magnetic clutch, idler pulley

Clang-Clack noise

When compressor is engaged

Magnetic clutch operation

Squawking (Belt sliding noise)

When compressor is engaged

V-belt

Whistling or Whooping noise

Immediately after the A/C is
engaged.

Expansion valve

Hissing or swishing noise

When A/C is engaged, but
decreases as flow is stable

Refrigerant flow

Rattling (Internal compressor)

When compressor is operating

Compressor internal part

Wooing (Resonant noise)

With A/C On, occurs at certain
speed.

Resonance of accessories

Cooing (Discharge pulsation
noise)

With A/C On or Off

Resonating noise with the vehicle
body

NOISE DESCRIPTION

POSSIBLE CAUSE

CHECK

REPAIR

Rumbling (Bearing
noise)

Bearing damage in rotor

Manual rotation of bearing Replace compressor

Rotor slipping on boss

Wear on compressor boss
surface

Replace compressor

Bearing damage in pulley Check alignment between

pulleys

Replace compressor

Clang-Clack noise

Hub to stator misaligned

Wear on inner clutch face Replace compressor

Gap between clutch
surface is too large

Check Air gap is within
specification

Replace compressor

Squawking (Belt sliding
noise)

Oil/water between the belt
and rotor surface

Oil and water
contamination

Clean

Low belt tension

Belt tension

Reset or Replace belt and
set tension to correct
specification

Whistling or Whooping
noise

Vibration of expansion
valve

Expansion valve

Replace TX valve

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