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Abnormal Noise Symptom Diagnosis of A/C SystemS6RW0D7214005
Abnormal Noise from Compressor
Abnormal Noise from Magnetic ClutchInsufficient air flow of
cooled airA/C evaporator clogged or frostedCheck A/C evaporator and evaporator
temperature sensor referring to “Evaporator
Inspection” and “Evaporator Temperature
Sensor Inspection”.
Air leaking from HVAC unit or air ductRepair as necessary.
Blower motor faultyCheck blower motor referring to “Blower Motor
Inspection in Section 7A”.
Wiring or grounding faultyRepair as necessary. Condition Possible cause Correction / Reference Item
Condition Possible cause Correction / Reference Item
During compressor
operation, a rumbling
noise is heard
proportional to engine
revolutionsInadequate clearance in scroll areaReplace compressor.
A loud noise is heard at a
certain rpm,
disproportionately to
engine revolutionLoose or faulty compressor drive beltAdjust drive belt tension or replace drive belt.
Loose compressor mounting boltsRetighten mounting bolts.
A loud rattle is heard at
low engine rpmLoose compressor clutch plate boltRetighten clutch plate bolt.
Replace compressor if it was operated in this
condition for a long time.
Condition Possible cause Correction / Reference Item
A rumbling noise is heard
when compressor is not
in operationWorn or damaged bearingsReplace magnet clutch assembly.
A chattering noise is
heard when compressor
is in operationFaulty magnet clutch clearance
(excessive clearance)Adjust magnet clutch clearance.
Worn magnet clutch friction surfaceReplace magnet clutch assembly.
Compressor oil leaked from shaft seal,
contaminating the friction surfaceReplace compressor body assembly.
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Abnormal Noise from Tubing
Abnormal Noise from Condenser Assembly
Abnormal Noise from Crankshaft Pulley
Abnormal Noise from Tension Pulley
Abnormal Noise from A/C Evaporator
Abnormal Noise from Blower MotorCondition Possible cause Correction / Reference Item
A droning noise is heard
from inside of the vehicle,
but not particularly
noticeable in engine
compartmentFaulty tubing clampsReposition clamps or increase the number of
clamps.
Resonance caused by pulsation from
variations in refrigerant pressureAttach a silencer to tubing, or modify its
position and length.
Condition Possible cause Correction / Reference Item
Considerable vibration in
condenser assemblyResonance from condenser assembly
bracket and bodyFirmly insert a silencer between condenser
assembly bracket and body.
Condition Possible cause Correction / Reference Item
A large rattling noise is
heard at idle or sudden
accelerationLoosen crankshaft pulley boltRetighten bolt.
Condition Possible cause Correction / Reference Item
Clattering noise is heard
from pulleyWorn or damaged bearingReplace tension pulley.
Pulley cranks upon
contactCracked or loose bracketReplace or retighten bracket.
Condition Possible cause Correction / Reference Item
Whistling sound is heard
from A/C evaporatorDepending on the combination of the
interior / exterior temperatures, engine
rpm and refrigerant pressure, the
refrigerant flowing out of the expansion
valve may, under certain conditions,
make a whistling soundAt times, slightly decreasing refrigerant volume
may stop this noise.
Inspect expansion valve and replace if faulty.
Condition Possible cause Correction / Reference Item
Blower motor emits a
chirping sound in
proportion to its speed of
rotationWorn or damaged motor brushes or
commutatorReplace blower motor.
Fluttering noise or large
droning noise is heard
from blower motorLeaves or other debris introduced from
fresh air inlet to blower motorRemove debris and make sure that the screen
at fresh air inlet is intact.
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Repair Instructions
Operation Procedure for Refrigerant ChargeS6RW0D7216001
WARNING!
• Your eyes should not be exposed to refrigerant (liquid).
Any liquid HFC-134a (R-134a) escaping by accident shows a temperature as low as approximately –
6 °C (21.2 °F) below freezing point. Should liquid HFC-134a (R-134a) is exposed to your eyes, it may
cause a serious injury. To protect your eyes from such accident, it is necessary to always wear
goggles. Should it occur that HFC-134a (R-134a) is exposed to your eyes, consult a doctor
immediately.
– Do not use your hand to rub the affected eye(s). Instead, use fresh cold water to splash it over the
affected area to gradually raise temperature of such area above freezing point.
– Obtain proper treatment as soon as possible from a doctor or eye specialist.
• Should the liquid refrigerant HFC-134a (R-134a) is exposed to your skin, the affected area should be
treated in the same manner as when skin is frostbitten or frozen.
• Do not handle refrigerant near any place where welding or steam cleaning is performed.
• Refrigerant should be kept in a cold and dark place. It should never be stored in any place where
temperature is high, e.g. where exposed to direct sun light, close to fire or inside vehicle (including
trunk room).
• Avoid breathing fume produced when HFC-134a (R-134a) is burned. Such fume may be hazardous to
your health.
Start evacuation.Start evacuation.
Stop evacuation.Stop evacuation.
15 minutes (above -100 kPa)15 minutes (above -100 kPa)
Wait 10 minutesWait 10 minutes
Check A/C system forCheck A/C system for
pressure tighteness.pressure tighteness.
Recharge A/C system withRecharge A/C system withrefrigerant.refrigerant.
Check A/C system for refrigerantCheck A/C system for refrigerantleaks and amount of refrigerantleaks and amount of refrigerantcharged.charged.
Performance testPerformance test
Inspect and repair connections.Inspect and repair connections.
If gauge showsIf gauge showsabnormal conditionsabnormal conditions
Recharge 430 20 g ofRecharge 430 20 g ofrefrigerant.refrigerant.
I5RW0A721011-01
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Recovery
When discharging refrigerant out of A/C system, always
recover it by using refrigerant recovery and recycling
equipment because discharging refrigerant HFC-134a
(R-134a) into atmosphere would cause adverse effect to
environments.
NOTE
• After recovering refrigerant from system,
the amount of removed compressor oil
must be measured for replenishing
compressor oil.
• When handling recovery and recycling
equipment, be sure to follow the
instruction manual for the equipment.
Replenishing Compressor Oil
It is necessary to replenish specified amount of
compressor oil to compressor from compressor suction
side hole (1) before evacuating and charging refrigerant.When charging refrigerant only
When charging refrigerant without replacing any
component, replenish the same amount of measured oil
when recovering refrigerant (if not measure, replenish 10
cm
3 (10 ml, 0.34 US.oz, 0.35 Imp.oz) oil).
When replacing compressor
CAUTION!
Be sure to use specified compressor oil or an
equivalent compressor oil.
Compressor oil is sealed in each new compressor by the
amount required for A/C system. Therefore, when using
a new compressor, drain the calculated amount of oil
from it.
“C” = “A” – “B”
“C”: Amount of oil to be drained
“A”: Amount of oil in a new compressor
“B”: Amount of oil in removed compressor
NOTE
Compressor assembly supplied from factory
is filled up with the following amount of oil.
: Compressor oil 99000–99015–00A
(MATSUSHITADENKI GU10)
Oil amount in compressor
75 + 10, – 0 cm3 (75 + 10, – 0 ml, 2.54 + 0.34, – 0
US.oz, 2.64 + 0.35, – 0 lmp.oz)
When replacing other parts
Replenish the following amount of oil to compressor.
Amount of compressor oil to be replenished
Evaporator: 15 cm3 (15 ml, 0.51 US.oz, 0.53 Imp.oz)
Condenser: 10 cm3 (10 ml, 0.34 US.oz, 0.35 Imp.oz)
Dryer: 10 cm3 (10 ml, 0.34 US.oz, 0.35 Imp.oz)
Hoses: 5 cm3 (5 ml, 0.17 US.oz, 0.18 Imp.oz) each
Pipes: 5 cm3 (5 ml, 0.17 US.oz, 0.18 Imp.oz) each
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1
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1. New compressor
2. Removed compressor
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Evacuation
CAUTION!
Do not evacuate before recovering
refrigerant in A/C system.
NOTE
Once air conditioning system circuit is
opened (exposed) to atmospheric air, system
must be evacuated by using a vacuum pump.
The A/C system should be attached with a
manifold gauge set, and should be evacuated
for approximately 15 minutes.
1) Connect high charging hose (1) and low charging
hose (2) of manifold gauge set (3) (special tool)
respectively as follows:
High charging hose → High pressure charging valve
(4) on discharge hose
Low charging hose → Low pressure charging valve
(5) on suction pipe
Special tool
(A): 09990–06020
2) Attach center charging hose (6) of manifold gauge
set to vacuum pump (7).
3) Operate vacuum pump, and then open discharge
side valve (Hi) (8) of manifold gauge set.
If there is no blockage in the system, there will be an
indication on high pressure gauge (9).
When this occurs, open the other side valve (Lo)
(10) of the set.
4) Approximately 10 minutes later, low pressure gauge
(11) should show a vacuum lower than –100 kPa (–
1.0 kgf/cm
2, –760 mmHg, –14.7 psi) providing no
leakage exists.
NOTE
• If the system does not show a vacuum
below –100 kPa (–1.0 kgf/cm
2, –760 mmHg,
–14.7 psi), close both valves, stop vacuum
pump and watch movement of low
pressure gauge.
• Increase in the gauge reading suggests
existence of leakage. In this case, repair
the system before continuing its
evacuation.
• If the gauge shows a stable reading
(suggesting no leakage), continue
evacuation.
5) Evacuation should be carried out for a total of at
least 15 minutes.
6) Continue evacuation until low pressure gauge
indicates a vacuum less than –100 kPa (–1.0 kgf/
cm
2, –760 mmHg, –14.7 psi), and then close both
valves.
7) Stop vacuum pump. Disconnect center charging
hose from pump inlet. Now, the system is ready for
charging refrigerant.
Checking A/C System for Pressure Leaks
After completing the evacuation, close manifold gauge
high pressure valve and low pressure valve and wait 10
minutes. Verify that low pressure gauge reading has not
changed.
CAUTION!
If the gauge reading moves closer to “0”,
there is a leak somewhere. Inspect the tubing
connections and make necessary
corrections. And then, evacuate system once
again and make sure that there are no leaks.
7
89 3, (A)
11
10
1
2
5
4
6
I7RW01721011-01