2010 INFINITI QX56 low oil pressure

REFRIGERATION SYSTEMHAC-11
< FUNCTION DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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REFRIGERATION SYSTEM
Refrigerant CycleINFOID:0000000005197357
REFRIGERANT FLOW
The refrigerant flows in the standard pattern, that is, through the compressor, the condenser with liquid tank,
through the front and rear evaporators, and back to the compressor. The refrigerant evaporation through the
evaporator coils are controlled by front and rear externally equalized expansion valves, located inside the front
and rear evaporator cases.
Refrigerant System ProtectionINFOID:0000000005197358
REFRIGERANT PRESSURE SENSOR
The refrigerant system is protected against excessively hi gh or low pressures by the refrigerant pressure sen-
sor, located on the condenser. If the system pressure rises above or falls below the specifications, the refriger-
ant pressure sensor detects the pressure inside the refrigerant line and sends a voltage signal to the ECM.
The ECM de-energizes the A/C relay to disengage the magnetic compressor clutch when pressure on the high
pressure side detected by refrigerant pressu re sensor is over about 2,746 kPa (28 kg/cm
2, 398 psi), or below
about 120 kPa (1.22 kg/cm
2, 17.4 psi).
WJIA1342E
Revision: April 20092010 QX56

INSUFFICIENT COOLINGHAC-113
< SYMPTOM DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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dard (usual) pressure, however, differs from vehicle to vehicle, refer to above table (Ambient air temperature-
to-operating pressure table).
Both High- and Low-pressure Sides are Too High
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
Gauge indication Refrigerant cycleProbable causeCorrective 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
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 val-
ue quickly drops by approx-
imately 196 kPa (2 kg/cm
2 ,
28 psi). It then decreases
gradually thereafter. Poor heat exchange in con-
denser
(After compressor operation
stops, high-pressure decreas-
es too slowly.)
↓
Air in refrigeration cycle
Evacuate and recharge system.
Engine tends to overheat. Engine cooling systems mal-
function. Check and repair engine cool-
ing 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 dis-
charge flow
• Expansion valve is open a lit- tle compared with the speci-
fication.
↓
Improper expansion valve ad-
justment Replace expansion valve.
AC359A
Gauge indication
Refrigerant cycleProbable causeCorrective 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 lo-
cated between compressor
and condenser are clogged or
crushed.
• Check and repair or replace
malfunctioning parts.
• Check oil for contamination.
AC360A
Revision: April 20092010 QX56

HAC-114
< SYMPTOM DIAGNOSIS >[AUTOMATIC AIR CONDITIONER]
INSUFFICIENT COOLING
Both High- and Low-pressure Sides are Too Low
Low-pressure Side Sometimes Becomes Negative
Gauge indication
Refrigerant cycleProbable causeCorrective 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 opera-
tion is improper.
↓
Damaged inside compressor
packings.
Replace compressor.
No temperature difference be-
tween high- and low-pressure
sides. Compressor pressure opera-
tion is improper.
↓
Damaged inside compressor
packings.
Replace compressor.
AC356A
Gauge indication
Refrigerant cycleProbable causeCorrective action
Both high- and low-pressure sides
are too low. • There is a big temperature
difference between liquid
tank outlet and inlet. Outlet
temperature is extremely
low.
• Liquid tank inlet and expan- sion valve are frosted. Liquid tank inside is slightly
clogged.
• Replace liquid tank.
• Check oil for contamination.
• Temperature of expansion valve inlet is extremely low
as compared with areas
near liquid tank.
• Expansion valve inlet may be frosted.
• Temperature difference oc-
curs somewhere in high-
pressure side. High-pressure pipe located be-
tween liquid tank and expan-
sion valve is clogged.
• Check and repair malfunc-
tioning parts.
• Check oil for contamination.
Expansion valve and liquid
tank are warm or only cool
when touched. Low refrigerant charge.
↓
Leaking fittings or compo-
nents. Check refrigerant system for
leaks. Refer to
HA-24, "
Check-
ing of Refrigerant Leaks".
There is a big temperature dif-
ference between expansion
valve inlet and outlet while the
valve itself is frosted. Expansion valve closes a little
compared with the specifica-
tion.
↓
1. Improper expansion
valve adjustment.
2. Malfunctioning expansion valve.
3. Outlet and inlet may be clogged. • Remove foreign particles by
using compressed air.
• Check oil for contamination.
An area of the low-pressure
pipe is colder than areas near
the evaporator outlet. Low-pressure pipe is clogged
or crushed. • Check and repair malfunc-
tioning parts.
• Check oil for contamination.
Air flow volume is too low. Evaporator is frozen. • Check intake sensor circuit.
Refer to HAC-83, "
Intake
Sensor Diagnosis Proce-
dure".
• Repair evaporator fins.
• Replace evaporator.
•Refer to HAC-48, "
Front
Blower Motor Component
Function Check".
AC353A
Revision: April 20092010 QX56

INSUFFICIENT COOLINGHAC-115
< SYMPTOM DIAGNOSIS > [AUTOMATIC AIR CONDITIONER]
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Low-pressure Side Becomes Negative
Gauge indication
Refrigerant cycleProbable causeCorrective action
Low-pressure side sometimes be-
comes negative. • Air conditioning system does
not function and does not cy-
clically cool the compart-
ment air.
• The system constantly func- tions for a certain period of
time after compressor is
stopped and restarted. Refrigerant does not discharge
cyclically.
↓
Moisture is frozen at expan-
sion valve outlet and inlet.
↓
Water is mixed with refrigerant.
• Drain water from refrigerant
or replace refrigerant.
• Replace liquid tank.
AC354A
Gauge indication Refrigerant cycleProbable causeCorrective action
Low-pressure side becomes nega-
tive. Liquid tank or front/rear side of
expansion valve′s pipe is frost-
ed or dewed. High-pressure side is closed
and refrigerant does not flow.
↓
Expansion valve or liquid tank
is frosted.Leave the system at rest until
no frost is present. Start it
again to check whether or not
the malfunction is caused by
water or foreign particles.
• If water is the cause, initially
cooling is okay. Then the wa-
ter freezes causing a block-
age. Drain water from
refrigerant or replace refrig-
erant.
• If due to foreign particles, re- move expansion valve and
remove the particles with dry
and compressed air (not
shop air).
• If either of the above meth- ods cannot correct the mal-
function, replace expansion
valve.
• Replace liquid tank.
• Check oil for contamination.
AC362A
Revision: April 20092010 QX56

LU-8
< ON-VEHICLE MAINTENANCE >
ENGINE OIL
ON-VEHICLE MAINTENANCE
ENGINE OIL
InspectionINFOID:0000000005149025
OIL LEVEL
• Before starting the engine make sure the vehicle is parked on a flatand level surface, then check the oil level. If the engine is already
running, turn it off and allow 10 minutes before checking.
• Check that the oil level is within the low (L) to high (H) range as indicated on the dipstick.
• If the engine oil level is out of range, add oil as necessary. Refer to
MA-13, "
Fluids and Lubricants".
OIL APPEARANCE
• Check the engine oil for a white milky appearance or excessive contamination.
• If the engine oil is milky, it is highly probable that it is contaminated with engine coolant. Repair the broken
parts.
OIL LEAKAGE
Check for oil leakage around the following areas:
•Oil pan
• Oil pan drain plug
• Oil pressure switch
• Oil filter
• Oil cooler
• Intake valve timing control cover
• Intake valve timing control solenoid valve
• Front cover
• Mating surface between cylinder block and cylinder head
• Mating surface between cylinder head and rocker cover
• Crankshaft oil seal (front and rear)
OIL PRESSURE CHECK
WARNING:
• Be careful not to burn yoursel f, as engine oil may be hot.
• Put the selector lever in the Park “P” position.
1. Check the engine oil level. Refer to LU-8, "
Inspection".
2. Remove engine front undercover using power tool.
3. Disconnect the oil pressure switch harness connector.
4. Remove the oil pressure switch (A).
SMA954C
WBIA0791E
Revision: April 20092010 QX56

ENGINE OILLU-9
< ON-VEHICLE MAINTENANCE >
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5. Install Tools.
6. Start the engine and warm it up to normal operating temperature.
7. Check the engine oil pressure with engine running under no-load.
Engine oil pressure [Engine oil temperature at 80
°C (175 °F)]
Unit: kPa (kg/cm2, psi)
CAUTION:
If the difference is extreme, check the oil passages and oil pump for leaks and blockages.
8. After the inspections, install oil pressure switch as follows:
a. Remove old liquid gasket adhering to oil pressure switch and engine.
b. Apply liquid gasket and tighten oil pressure switch to the specification. Use Genuine RTV Silicone Seal ant or equivalent. Refer to GI-15, "
Recommended Chemical Prod-
ucts and Sealants".
c. After warming up engine, make sure there is no leakage of engine oil with engine running.
Changing Engine OilINFOID:0000000005149026
WARNING:
• Be careful not to burn yourself, as the engine oil is hot.
• Prolonged and repeated contact with used engine oil may cause skin cancer. Try to avoid direct skin contact with used
engine oil. If skin contact is made, wash thoroughly with soap
or hand cleaner as soon as possible.
1. Remove engine front undercover using power tool.
2. Warm up engine, and check for oil leakage from engine compo- nents. Refer to LU-8, "
Inspection".
3. Stop engine and wait for 10 minutes.
4. Loosen oil filler cap, then remove drain plug.
5. Drain engine oil.
6. Install drain plug with new washer. CAUTION:
• Be sure to clean drain plug and install with new washer.
7. Refill with new engine oil. Refer to MA-13, "
Fluids and Lubricants".
Engine oil capacity (Approximate):
Tool number : ST25051001 (J-25695-1)
: ST25052000 (J-25695-2)
WBIA0571E
Engine Speed Approximate Discharge Oil Pressure
Idle speed More than 98 (1.0, 14)
2,000 rpm More than 294 (3.0, 43)
Oil pressure switch torque : 14.8 N·m (1.5 kg-m, 11 ft-lb)
Oil pan drain plug : 34.3 N·m (3.5 kg-m, 25 ft-lb)
KBIA2498E
Revision: April 20092010 QX56

LU-18
< SERVICE DATA AND SPECIFICATIONS (SDS)
SERVICE DATA AND SPECIFICATIONS (SDS)
SERVICE DATA AND SPECIFICATIONS (SDS)
SERVICE DATA AND SPECIFICATIONS (SDS)
Standard and LimitINFOID:0000000005149033
OIL PRESSURE
Unit: kPa (kg/cm2, psi)
OIL PUMP
Unit: mm (in)
REGULATOR VALVE
Unit: mm (in)
ENGINE OIL CAPACITY (APPROXIMATE)
Unit: (US qt, Imp qt)
Engine speed Approximate discharge oil pressure
Idle speed More than 98 (1.0, 14)
2,000 rpm More than 294 (3.0, 43)
Body to outer rotor radial clearance0.114 - 0.200 (0.0045 - 0.0079)
Inner rotor to outer rotor tip clearance Below 0.180 (0.0071)
Body to inner rotor side clearance 0.030 - 0.070 (0.0012 - 0.0028)
Body to outer rotor side clearance 0.030 - 0.090 (0.0012 - 0.0035)
Inner rotor to brazed portion of housing clearance 0.045 - 0.091 (0.0018 - 0.0036)
Regulator valve to oil pump cover clearance 0.040 - 0.097 (0.0016 - 0.0038)
Drain and refillWith oil filter change 6.5 (6-7/8, 5-3/4)
Without oil filter change
6.2 (6-1/2, 5-1/2)
Dry engine (engine overhaul) 7.6 (8, 6-3/4)
Revision: April 20092010 QX56

ENGINE MAINTENANCEMA-17
< ON-VEHICLE MAINTENANCE >
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• Pull negative-pressure valve to open it and make sure that it closes
completely when released.
• Make sure that there is no dirt or damage on the valve seat of radi-
ator cap negative-pressure valve.
• Make sure that there are no unusualness in the opening and clos- ing conditions of negative-pressure valve.
ENGINE COOLANT : Chang ing Engine CoolantINFOID:0000000005403134
WARNING:
• To avoid being scalded, never change the coolant when the engine is hot.
• Wrap a thick cloth around the cap to carefully remo ve the cap. First, turn the cap a quarter of a turn
to release any built-up pressure, then push down and turn the cap all the way to remove it.
DRAINING ENGINE COOLANT
1. Turn ignition switch ON and set temperature control lever all the way to HOT position or the highest tem-
perature position. Wait 10 seconds and turn ignition switch OFF.
2. Remove the engine front undercover using power tool.
3. Open the radiator drain plug at the bottom of the radiator, and remove the radiator filler cap. This is the only step required
when partially draining the cooling system (radiator only).
CAUTION:
Do not to allow the coolant to contact the drive belts.
4. When draining all of the coolant in the system for engine removal or repair, it is necessary to drain the cylinder block.
Remove the RH cylinder block drain plug to drain the right bank
and the oil cooler hose to drain the left bank as shown.
SMA967B
WBIA0391E
PBIC0146E
WBIA0392E
Revision: April 20092010 QX56