Infiniti EX35. Manual - part 887
REFRIGERATION SYSTEM SYMPTOMS
HA-7
< SYMPTOM DIAGNOSIS >
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SYMPTOM DIAGNOSIS
REFRIGERATION SYSTEM SYMPTOMS
Trouble Diagnosis For Unusual Pressure
INFOID:0000000003545451
Diagnose using a manifold gauge whenever system’s high and/or low side pressure(s) is/are unusual. The
marker above the gauge scale in the following tables indicates the standard (usual) pressure range. Refer to
above table (Ambient air temperature-to-operating pressure table) since the standard (usual) pressure, how-
ever, differs from vehicle to vehicle.
Symptom Table
INFOID:0000000003545452
Gauge indication
Refrigerant cycle
Probable cause
Corrective action
Both high- and low-pressure sides
are too high.
The pressure returns to nor-
mal is reduced soon after wa-
ter is splashed on condenser.
Excessive refrigerant charge in
refrigeration cycle.
Reduce refrigerant until speci-
fied pressure is obtained.
Air suction by cooling fan is in-
sufficient.
Insufficient condenser cooling
performance.
↓
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
reading quickly drops by
approximately 196 kPa (2
kg/cm
2
, 28 psi). It then de-
creases gradually thereaf-
ter.
Poor heat exchange in con-
denser
(After compressor operation
stops, high-pressure decreas-
es too slowly).
↓
Air in refrigeration cycle.
Evacuate repeatedly and re-
charge system.
Engine tends to overheat.
Engine cooling systems mal-
function.
Check and repair each engine
cooling system.
• An area of the low-pressure
pipe is colder than areas
near the evaporator outlet.
• Low-pressure pipe is some-
times covered with frost.
• Excessive liquid refrigerant
on low-pressure side.
• Excessive refrigerant dis-
charge flow.
• Expansion valve is open a lit-
tle compared with the speci-
fication.
↓
Improper expansion valve ad-
justment.
Replace expansion valve.
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 lo-
cated between compressor
and condenser are clogged or
crushed.
• Check and repair or replace
malfunctioning parts.
• Check lubricant for contami-
nation.
AC359A
AC360A