MTC-16
< SERVICE INFORMATION >
OIL
OIL
Maintenance of Oil Quantity in CompressorINFOID:0000000001704289
The oil in the compressor circulates through the system with the refrigerant. Add oil to compressor when
replacing any component or after a large refrigerant leakage occurred. It is important to maintain the specified
amount.
If oil quantity is not maintained properly, the following malfunctions may result:
• Lack of oil: May lead to a seized compressor.
• Excessive oil: Inadequate cooling (thermal exchange interference)
OIL
OIL RETURN OPERATION
Adjust the oil quantity according to the test group shown below.
1.CHECK OIL RETURN OPERATION
Can oil return operation be performed?
• A/C system works properly.
• There is no evidence of a large amount of oil leakage.
CAUTION:
If excessive oil leakage is noted, do not perform the oil return operation.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
2.PERFORM OIL RETURN OPERATION, PROCEEDING AS FOLLOWS
1. Start engine, and set the following conditions:
- Engine speed: Idling to 1,200 rpm
- A/C blower switch: ON
- Blower speed: Max. position
- Temp. control: Optional [Set so that intake air temperature is 25° to 30°C (77° to 86° F)].
- Intake position: Recirculation (REC)
2. Perform oil return operation for about 10 minutes.
3. Stop engine.
>> GO TO 3.
3.CHECK REPLACEMENT PART
Should the compressor be replaced?
YES >> GO TO "OIL ADJUSTING PROCEDURE FOR COMPRESSOR REPLACEMENT".
NO >> GO TO "OIL ADJUSTING PROCEDURE FOR COMPONENTS REPLACEMENT EXCEPT COM-
PRESSOR".
OIL ADJUSTING PROCEDURE FOR COMPONENTS REPLACEMENT EXCEPT COMPRESSOR
After replacing any of the following major components, add the correct amount of oil to the system.
Amount Of Oil To Be Added
TYPE 1 Compressor (CR-10) : NISSAN A/C System Oil Type R
TYPE 2 Compressor (CSV511) : NISSAN A/C System Oil Type S
Part replacedOil to be added to system
Remarks
Amount of oil
m (US fl oz, Imp fl oz)
Evaporator 35 (1.2, 1.2) -
Condenser 15 (0.5, 0.5) -
Liquid tank 5 (0.2, 0.2) -
MTC-50
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
High-pressure Side is Too High and Low-pressure Side is Too Low
High-pressure Side is Too Low and Low-pressure Side is Too High
Both High- and Low-pressure Sides are Too Low
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure
sides are too high.Pressure is reduced soon af-
ter water is splashed on con-
denser.Excessive refrigerant charge in refrig-
eration cycle.Reduce refrigerant until
specified pressure is ob-
tained.
Air suction by cooling fan is in-
sufficient.Insufficient condenser cooling perfor-
mance.
↓
1. Condenser fins are clogged.
2. Improper fan rotation of cooling
fan.• Clean condenser.
• Check and repair cooling
fan if necessary.
• Low-pressure pipe is not
cold.
• When compressor is
stopped high-pressure val-
ue quickly drops by approx-
imately 196 kPa (1.96 bar, 2
kg/cm
2 , 28 psi). It then de-
creases gradually thereaf-
ter.Poor heat exchange in condenser
(After compressor operation stops,
high-pressure decreases too slowly.).
↓
Air in refrigeration cycle.Evacuate repeatedly and
recharge system.
Engine tends to overheat. Engine cooling systems malfunction.Check and repair each en-
gine cooling system.
• An area of the low-pressure
pipe is colder than areas
near the evaporator outlet.
• Plates are sometimes cov-
ered with frost.• Excessive liquid refrigerant on low-
pressure side.
• Excessive refrigerant discharge
flow.
• Expansion valve is open a little
compared with the specification.
↓
Improper expansion valve adjust-
ment.Replace expansion valve.
AC359A
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too high
and low-pressure side is too low.
Upper side of condenser and
high-pressure side are hot,
however, liquid tank is not so
hot.High-pressure tube or parts located
between compressor and condenser
are clogged or crushed.• Check and repair or re-
place malfunctioning
parts.
• Check oil for contami-
nation.
AC360A
Gauge indication Refrigerant cycle Probable cause Corrective action
High-pressure side is too low
and low-pressure side is too
high.High- and low-pressure sides
become equal soon after com-
pressor operation stops.Compressor pressure operation
is improper.
↓
Damaged inside compressor
packings.Replace compressor.
No temperature difference be-
tween high- and low-pressure
sides.Compressor pressure operation
is improper.
↓
Damaged inside compressor
packings.Replace compressor.
AC356A
