2006 INFINITI M35 engine cooling

TROUBLE DIAGNOSIS
ATC-105
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Revision: 2006 January2006 M35/M45
TROUBLE DIAGNOSIS FOR UNUSUAL PRESSURE
Whenever system’s high and/or low side pressure(s) is/are unusual, diagnose using a manifold gauge. The
marker above the gauge scale in the following tables indicates the standard (usual) pressure range. Since the
standard (usual) pressure, however, differs from vehicle to vehicle, refer to above table (Ambient air tempera-
ture-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
Gauge indication Refrigerant cycle Probable cause Corrective action
Both high- and low-pressure sides
are too high.The pressure returns to nor-
mal soon after water is
splashed on condenser.Excessive refrigerant charge
in refrigeration cycle.Reduce refrigerant until speci-
fied pressure is obtained.
Air suction by cooling fan is
insufficient.Insufficient condenser cooling
performance.
1. Condenser fins are clogged.
2. Improper fan rotation of
cooling fan.
Clean condenser.
Check and repair cooling fan
as necessary.
Low-pressure pipe is not
cold.
When compressor is
stopped high-pressure
value quickly drops by
approximately 196 kPa (2
kg/cm
2 , 28 psi). It then
decreases gradually there-
after.Poor heat exchange in con-
denser
(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 mal-
function.Check and repair each engine
cooling system.
An area of the low-pres-
sure pipe is colder than
areas near the evaporator
outlet.
Low-pressure pipe is
sometimes covered with
frost.
Excessive liquid refrigerant
on low-pressure side.
Excessive refrigerant dis-
charge flow.
Expansion valve is open a
little compared with the
specification.

Improper expansion valve
adjustment.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 replace
malfunctioning parts.
Check lubricant for contami-
nation.
AC360A

HEATER & COOLING UNIT ASSEMBLY
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Revision: 2006 January2006 M35/M45
HEATER & COOLING UNIT ASSEMBLYPFP:27110
Removal and InstallationNJS000HF
REMOVAL
1. Use a refrigerant collecting equipment (for HFC-134a) to discharge the refrigerant.
2. Drain coolant from cooling system. Refer to CO-11, "
Changing Engine Coolant" (VQ35DE) or CO-40,
"Changing Engine Coolant" (VK45DE).
3. Remove cowl top cover. Refer to EI-18, "
COWL TOP" .
4. Disconnect low-pressure flexible hose and high-pressure pipe 1
from evaporator.
a. Set a disconnector [high-pressure side (SST: 9253089908), low-
pressure side (SST: 9253089916)] on A/C piping.
b. Slide a disconnector toward vehicle front until it clicks.
c. Slide A/C piping toward vehicle front and disconnect it.
CAUTION:
Cap or wrap the joint of the pipe with suitable material such
as vinyl tape to avoid the entry of air.
5. Remove electric throttle control actuator. Refer to EM-19,
"INTAKE MANIFOLD COLLECTOR" (VQ35DE) or EM-179,
"INTAKE MANIFOLD" (VK45DE).
6. Disconnect two heater hoses from heater core.
7. Remove instrument panel & pad. Refer to IP-10, "
INSTRUMENT PANEL ASSEMBLY" .
8. Remove blower unit. Refer to ATC-130, "
BLOWER UNIT" .
9. Remove clips of vehicle harness from steering member.
10. Remove mounting nuts and bolts, and then remove instrument stays.
RJIA4117E
RJIA4118E
RJIA4119E

HEATER & COOLING UNIT ASSEMBLY
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Revision: 2006 January2006 M35/M45
CAUTION:
Replace O-rings of A/C piping with new ones, and then apply compressor oil to it when installing
it.
Female-side piping connection is thin and easy to deform. Slowly insert the male-side piping
straight in axial direction.
Insert piping securely until a click is heard.
After piping connection is completed, pull male-side piping by hand to make sure that connection
does not come loose.
When recharging refrigerant, check for leaks.
NOTE:
When filling radiator with coolant, refer to CO-11, "Changing Engine Coolant" (VQ35DE) or CO-40,
"Changing Engine Coolant" (VK45DE).
Recharge the refrigerant.
Heater & cooling unit assembly mounting bolt
: 6.9 Nꞏm (0.7 kg-m, 61 in-lb)
Instrument stay mounting nut and bolt
: 12 Nꞏm (1.25 kg-m, 9 ft-lb)

REFRIGERANT LINES
ATC-165
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Revision: 2006 January2006 M35/M45
INSTALLATION
Install liquid tank, and then install liquid tank bracket on condenser.
CAUTION:
Make sure liquid tank bracket is securely installed at protru-
sion of condenser. (Make sure liquid tank bracket does not
move to a position below center of liquid tank.)
Replace O-rings of A/C piping with new ones, and then
apply compressor oil to it when installing it.
When recharging refrigerant, check for leaks.
Removal and Installation of CondenserNJS000HU
REMOVAL
1. Use a refrigerant collecting equipment (for HFC-134a) to discharge the refrigerant.
2. Remove engine cover. Refer to EM-14, "
ENGINE ROOM COVER" (VQ35DE) or EM-173, "ENGINE
ROOM COVER" (VK45DE).
3. Remove air cleaner case, air hose and air duct. Refer to EM-17, "
AIR CLEANER AND AIR DUCT"
(VQ35DE) or EM-177, "AIR CLEANER AND AIR DUCT" (VK45DE).
4. Remove engine under cover, using power tools.
5. Drain engine coolant. Refer to CO-11, "
Changing Engine Coolant" (VQ35DE) or CO-40, "Changing
Engine Coolant" (VK45DE).
6. Remove radiator fan shroud with cooling fan after (VK45DE). Refer to CO-51, "
COOLING FAN" .
7. Remove mounting clips and bolts, and then remove bracket.
8. Remove radiator upper mount, remove radiator and condenser
to the engine side.
9. Remove mounting bolt from high-pressure flexible hose bracket.
10. Remove high-pressure pipe1 from vehicle clip.
RJIA1441E
RJIA4173E
RJIA4174E

ATC-172
REFRIGERANT LINES
Revision: 2006 January2006 M35/M45
CHECKING PROCEDURE
To prevent inaccurate or false readings, make sure there is no refrigerant vapor, shop chemicals, or cigarette
smoke in the vicinity of the vehicle. Perform the leak test in calm area (low air/wind movement) so that the
leaking refrigerant is not dispersed.
1. Stop engine.
2. Connect a suitable A/C manifold gauge set (SST: J-39183)to the A/C service valves.
3. Check if the A/C refrigerant pressure is at least 345 kPa (3.52 kg/cm
2 , 50 psi) above 16C (61F). If less
than specification, recover/evacuate and recharge the system with the specified amount of refrigerant.
NOTE:
At temperatures below 16
C (61F), leaks may not be detected since the system may not reach 345 kPa
(3.52 kg/cm
2 , 50 psi).
4. Perform the leak test from the high-pressure side (compressor discharge a to evaporator inlet h) to the
low-pressure side [evaporator drain hose i to shaft seal m(VQ35DE) or n(VK45DE)]. Refer to ATC-153,
"Components" . Perform a leak check for the following areas carefully. Clean the component to be
checked and move the leak detected probe completely around the connection/component.
Compressor
Check the fitting of high- and low-pressure flexible hoses, relief valve and shaft seal.
Condenser
Check the fitting of high-pressure flexible hose and pipe.
Liquid tank
Check the fitting of refrigerant pressure sensor.
Service valves
Check all around the service valves. Ensure service valve caps are secured on the service valves (to pre-
vent leaks).
NOTE:
After removing A/C manifold gauge set from service valves, wipe any residue from valves to prevent any
false readings by leak detector.
Cooling unit (Evaporator)
With engine OFF, turn blower fan on “High” for at least 15 seconds to dissipate any refrigerant trace in the
cooling unit. Wait a minimum of 10 minutes accumulation time (refer to the manufacturer’s recommended
procedure for actual wait time) before inserting the leak detector probe into the drain hose.
Keep the probe inserted for at least 10 seconds. Use caution not to contaminate the probe tip with water
or dirt that may be in the drain hose.
5. If a leak detector detects a leak, verify at least once by blowing compressed air into area of suspected
leak, then repeat check as outlined above.
6. Do not stop when one leak is found. Continue to check for additional leaks at all system components.
If no leaks are found, perform steps 7 - 10.
7. Start the engine.
8. Set the A/C control as follows;
a. A/C switch: ON
b. MODE door position: VENT (Ventilation)
c. Intake door position: Recirculation
d. Temperature setting: Max. cold
e. Fan speed: High
9. Run engine at 1,500 rpm for at least 2 minutes.
10. Stop the engine and perform leak check again following steps 4
through 6 above.
Refrigerant leaks should be checked immediately after stopping
the engine. Begin with the leak detector at the compressor. The
pressure on the high-pressure side will gradually drop after
refrigerant circulation stops and pressure on the low-pressure
side will gradually rise, as shown in the graph. Some leaks are
more easily detected when pressure is high.
11. Before connecting recovery/recycling recharging equipment to
vehicle, check recovery/recycling recharging equipment gauges.
SHA839E

CO-1
ENGINE COOLING SYSTEM
B ENGINE
CONTENTS
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SECTION CO
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Revision: 2006 January2006 M35/M45
ENGINE COOLING SYSTEM
VQ35DE
PRECAUTIONS .......................................................... 3
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 3
Precautions for Liquid Gasket .................................. 3
REMOVAL OF LIQUID GASKET SEALING .......... 3
LIQUID GASKET APPLICATION PROCEDURE ..... 3
PREPARATION ........................................................... 5
Special Service Tools ............................................... 5
Commercial Service Tools ........................................ 6
OVERHEATING CAUSE ANALYSIS .......................... 7
Troubleshooting Chart .............................................. 7
COOLING SYSTEM .................................................... 9
Cooling Circuit .......................................................... 9
System Chart ......................................................... 10
ENGINE COOLANT ...................................................11
Inspection ................................................................ 11
LEVEL CHECK .................................................... 11
LEAK CHECK ...................................................... 11
Changing Engine Coolant ....................................... 11
DRAINING ENGINE COOLANT .......................... 11
REFILLING ENGINE COOLANT ........................ 12
FLUSHING COOLING SYSTEM ......................... 13
RADIATOR ................................................................ 14
Components ........................................................... 14
Removal and Installation ........................................ 14
REMOVAL ........................................................
... 14
INSTALLATION ................................................... 16
INSPECTION AFTER INSTALLATION ............... 16
Checking Radiator Cap .......................................... 16
Checking Radiator .................................................. 16
RADIATOR (ALUMINUM TYPE) .............................. 18
Components ........................................................... 18
Disassembly and Assembly ................................... 18
PREPARATION ................................................... 18
DISASSEMBLY ................................................... 18
ASSEMBLY ......................................................... 19
INSPECTION ...................................................... 21COOLING FAN .......................................................... 22
Components ........................................................... 22
Removal and Installation ........................................ 22
REMOVAL ........................................................
... 22
INSTALLATION ................................................... 22
INSPECTION AFTER INSTALLATION ................ 22
Disassembly and Assembly .................................... 23
DISASSEMBLY ................................................... 23
INSPECTION AFTER DISASSEMBLY ................ 23
ASSEMBLY ......................................................... 23
WATER PUMP .......................................................... 24
Components ........................................................... 24
Removal and Installation ........................................ 24
REMOVAL ........................................................
... 24
INSPECTION AFTER REMOVAL ....................... 26
INSTALLATION ................................................... 26
INSPECTION AFTER INSTALLATION ................ 28
WATER INLET AND THERMOSTAT ASSEMBLY .... 29
Components ........................................................... 29
Removal and Installation ........................................ 29
REMOVAL ........................................................
... 29
INSPECTION AFTER REMOVAL ....................... 30
INSTALLATION ................................................... 30
INSPECTION AFTER INSTALLATION ................ 30
WATER OUTLET AND WATER PIPING ................... 31
Components ........................................................... 31
Removal and Installation ........................................ 31
REMOVAL ........................................................
... 31
INSTALLATION ................................................... 32
INSPECTION AFTER INSTALLATION ................ 32
SERVICE DATA AND SPECIFICATIONS (SDS) ...... 33
Standard and Limit .................................................. 33
ENGINE COOLANT CAPACITY (APPROXI-
MATE) .................................................................. 33
RADIATOR .......................................................
... 33
THERMOSTAT .................................................... 33

CO-2Revision: 2006 January2006 M35/M45
VK45DE
PRECAUTIONS ......................................................... 34
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” ................................................................. 34
PREPARATION ......................................................... 35
Special Service Tools ............................................. 35
Commercial Service Tools ...................................... 35
OVERHEATING CAUSE ANALYSIS ........................ 36
Troubleshooting Chart ............................................ 36
COOLING SYSTEM .................................................. 38
Cooling Circuit ........................................................ 38
System Chart .......................................................... 39
ENGINE COOLANT .................................................. 40
Inspection ............................................................... 40
LEVEL CHECK .................................................... 40
LEAK CHECK ...................................................... 40
Changing Engine Coolant ....................................... 40
DRAINING ENGINE COOLANT .......................... 40
REFILLING ENGINE COOLANT ......................... 41
FLUSHING COOLING SYSTEM ......................... 42
RADIATOR ................................................................ 43
Components ........................................................... 43
Removal and Installation ........................................ 43
REMOVAL ........................................................
... 43
INSTALLATION .................................................... 45
INSPECTION AFTER INSTALLATION ................ 45
Checking Radiator Cap .......................................... 45
Checking Radiator .................................................. 45
RADIATOR (ALUMINUM TYPE) ............................... 47
Components ........................................................... 47
Disassembly and Assembly .................................... 47
PREPARATION ................................................... 47
DISASSEMBLY ................................................... 47
ASSEMBLY ......................................................... 48
INSPECTION ....................................................... 50COOLING FAN .......................................................... 51
Components ............................................................ 51
Removal and Installation ......................................... 51
REMOVAL ............................................................ 51
INSTALLATION .................................................... 51
INSPECTION AFTER INSTALLATION ................ 51
Disassembly and Assembly .................................... 52
DISASSEMBLY .................................................... 52
INSPECTION AFTER DISASSEMBLY ................ 52
ASSEMBLY .......................................................... 52
WATER PUMP ........................................................... 53
Components ............................................................ 53
Removal and Installation ......................................... 53
REMOVAL ............................................................ 53
INSPECTION AFTER REMOVAL ........................ 54
INSTALLATION .................................................... 54
INSPECTION AFTER INSTALLATION ................ 54
THERMOSTAT AND WATER CONTROL VALVE ..... 55
Components ............................................................ 55
Removal and Installation ......................................... 55
REMOVAL ............................................................ 55
INSPECTION AFTER REMOVAL ........................ 56
INSTALLATION .................................................... 56
INSPECTION AFTER INSTALLATION ................ 57
SERVICE DATA AND SPECIFICATIONS (SDS) ...... 58
Standard and Limit .................................................. 58
ENGINE COOLANT CAPACITY (APPROXI-
MATE) .................................................................. 58
RADIATOR ........................................................... 58
THERMOSTAT ..................................................... 58
WATER CONTROL VALVE .................................. 58

OVERHEATING CAUSE ANALYSIS
CO-7
[VQ35DE]
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Revision: 2006 January2006 M35/M45
OVERHEATING CAUSE ANALYSISPFP:00012
Troubleshooting ChartNBS004QN
Symptom Check items
Cooling sys-
tem parts
malfunctionPoor heat transferWater pump malfunction Worn or loose drive belt
— Thermostat stuck closed —
Damaged finsDust contamination or
paper clogging
Physical damage
Clogged radiator cooling
tubeExcess foreign material
(rust, dirt, sand, etc.)
Reduced air flowCooling fan does not oper-
ate
Fan assembly — High resistance to fan rota-
tion
Damaged fan blades
Damaged radiator shroud — — —
Improper engine coolant
mixture ratio
———
Poor engine coolant quality — Engine coolant density —
Insufficient engine coolantEngine coolant leaksCooling hoseLoose clamp
Cracked hose
Water pump Poor sealing
Radiator capLoose
Poor sealing
RadiatorO-ring for damage, deterio-
ration or improper fitting
Cracked radiator tank
Cracked radiator core
Reservoir tank Cracked reservoir tank
Overflowing reservoir tankExhaust gas leaks into
cooling systemCylinder head deterioration
Cylinder head gasket dete-
rioration