Ac system INFINITI QX4 2001 Factory Service Manual

Cooling CircuitNBLC0015
SLC321B
SLC325B
ENGINE COOLING SYSTEM
Cooling Circuit
LC-10

System CheckNBLC0016WARNING:
Never remove the radiator cap when the engine is hot; serious
burns could be caused by high pressure fluid escaping from
the radiator.
Wrap a thick cloth around the cap and carefully remove it by
turning it a quarter turn to allow built-up pressure to escape
and then turn the cap all the way off.
CHECKING COOLING SYSTEM HOSESNBLC0016S01Check hoses for improper attachment, leaks, cracks, damage,
loose connections, chafing and deterioration.
CHECKING RADIATORNBLC0016S02Check radiator for mud or clogging. If necessary, clean radiator as
follows.
IBe careful not to bend or damage the radiator fins.
IWhen radiator is cleaned without removal, remove all sur-
rounding parts such as cooling fan, radiator shroud and horns.
Then tape the harness and connectors to prevent water from
entering.
1. Apply water by hose to the back side of the radiator core ver-
tically downward.
2. Apply water again to all radiator core surfaces once per
minute.
3. Stop washing if any stains no longer flow out from the radia-
tor.
4. Blow air into the back side of radiator core vertically downward.
IUse compressed air lower than 490 kPa (5 kg/cm
2, 71 psi) and
keep distance more than 30 cm (11.8 in).
5. Blow air again into all the radiator core surfaces once per
minute until no water sprays out.
SLC755A
CHECKING RADIATOR CAPNBLC0016S03To check radiator cap, apply pressure to cap with a tester.
Radiator cap relief pressure:
Standard
78-98kPa
(0.8 - 1.0 kg/cm
2, 11 - 14 psi)
Limit
59-98kPa
(0.6 - 1.0 kg/cm
2,9-14psi)
SMA967B
Pull the negative pressure valve to open it.
Check that it closes completely when released.
GI
MA
EM
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ENGINE COOLING SYSTEM
System Check
LC-11

SLC756A
CHECKING COOLING SYSTEM FOR LEAKSNBLC0016S04To check for leakage, apply pressure to the cooling system with a
tester.
Testing pressure:
157 kPa (1.6 kg/cm
2, 23 psi)
CAUTION:
Higher than the specified pressure may cause radiator
damage.
Water Pump
REMOVAL AND INSTALLATIONNBLC0017CAUTION:
IWhen removing water pump assembly, be careful not to
get coolant on drive belt.
IWater pump cannot be disassembled and should be
replaced as a unit.
IAfter installing water pump, connect hose and clamp
securely, then check for leaks using radiator cap tester.
SLC326B
SLC327B
REMOVALNBLC00181. Remove under cover.
2. Remove suspension member stay.
3. Drain coolant from radiator.
4. Remove radiator shrouds.
5. Remove drive belts.
6. Remove cooling fan.
7. Remove water drain plug on water pump side of cylinder block.
8. Remove chain tensioner cover and water pump cover.
ENGINE COOLING SYSTEM
System Check (Cont'd)
LC-12

SLC328B
9. Pushing timing chain tensioner sleeve, apply a stopper pin so
it does not return. Then remove the chain tensioner assembly.
SLC941A
10. Remove the 3 water pump fixing bolts. Secure a gap between
water pump gear and timing chain, by turning crankshaft pul-
ley 20É backwards.
JLC357B
11. Put M8 bolts to two water pump fixing bolt holes.
GI
MA
EM
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ENGINE COOLING SYSTEM
Water Pump (Cont'd)
LC-13

SLC116B
12. Tighten M8 bolts by turning half turn alternately until they reach
timing chain rear case.
IIn order to prevent damages to water pump or timing chain rear
case, do not tighten one bolt continuously. Always turn each
bolt half turn each time.
13. Lift up water pump and remove it.
IWhen lifting up water pump, do not allow water pump gear to
hit timing chain.
SLC943A
INSPECTIONNBLC00191. Check for badly rusted or corroded body assembly.
2. Check for rough operation due to excessive end play.
SLC244B
INSTALLATIONNBLC00201. Apply engine oil and coolant to O-rings as shown in the figure.
ENGINE COOLING SYSTEM
Water Pump (Cont'd)
LC-14

SLC031B
2. Install water pump.
IDo not allow cylinder block to nip O-rings when installing
water pump.
SLC944A
3. Before installing, remove all traces of liquid gasket from mat-
ing surface of water pump cover and chain tensioner cover
using a scraper.
Also remove traces of liquid gasket from mating surface of
front cover.
SLC945AA
4. Apply a continuous bead of liquid gasket to mating surface of
chain tensioner cover and water pump cover.
SLC156B
5. Return the crankshaft pulley to its original position by turning
it 20É forward.
SLC961A
6. Install timing chain tensioner, then remove the stopper pin.
IWhen installing the timing chain tensioner, engine oil
should be applied to the oil hole and tensioner.
IAfter starting engine, let idle for three minutes, then rev
engine up to 3,000 rpm under no load to purge air from the
high-pressure chamber of the chain tensioners. The
engine may produce a rattling noise. This indicates that
air still remains in the chamber and is not a matter of
concern.
7. Reinstall any parts removed in reverse order of removal.
GI
MA
EM
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ENGINE COOLING SYSTEM
Water Pump (Cont'd)
LC-15

Thermostat
REMOVAL AND INSTALLATIONNBLC0021
SLC329B
SLC962AA
1. Remove under cover.
2. Remove suspension member stay.
3. Drain coolant from radiator.
4. Remove drive belts.
5. Remove water drain plug on water pump side of cylinder block.
6. Disconnect lower radiator hose.
7. Remove water inlet and thermostat assembly.
IDo not disassemble water inlet and thermostat. Replace
them as a unit, if necessary.
SLC948A
8. Install thermostat with jiggle valve facing upward.
IAfter installation, run engine for a few minutes, and check
for leaks.
IBe careful not to spill coolant over engine compartment.
Use a rag to absorb coolant.
9. Reinstall any removed parts in reverse order of removal.
SLC949A
INSPECTIONNBLC00221. Check valve seating condition at ordinary room temperatures.
It should seat tightly.
2. Check valve opening temperature and maximum valve lift.
Standard
Valve opening temperature 76.5ÉC (170ÉF)
Valve lift More than 8.6 mm/90ÉC
(0.339 in/194ÉF)
ENGINE COOLING SYSTEM
Thermostat
LC-16

3. Then check if valve closes at 5ÉC (9ÉF) below valve opening
temperature.
Water Control Valve
REMOVAL AND INSTALLATIONNBLC0032
SLC330B
1. Water outlet housing
2. Water control valve
3. Water outlet4. Water hose
5. Cylinder block water outlet
6. Thermal transmitter7. Engine coolant temperature sen-
sor
1. Release fuel pressure.
Refer to EC-39, ªFuel Pressure Releaseº.
2. Remove under cover.
3. Remove suspension member stay.
4. Drain coolant from radiator.
5. Remove engine cover.
6. Remove air duct with air cleaner assembly.
7. Disconnect wires, hoses, harness and so on.
8. Remove upper intake manifold corrector.
9. Remove intake manifold corrector support bolts.
10. Remove lower intake manifold corrector.
11. Disconnect injector harness connectors.
12. Remove injector tube.
13. Remove intake manifold.
14. Remove water outlet housing and water control valve.
GI
MA
EM
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ENGINE COOLING SYSTEM
Thermostat (Cont'd)
LC-17

SLC334B
15. Install water control valve and water outlet housing.
a. Install gum ring to thermostat.
b. Point the arrow on the upper surface of the valve to the front
of the engine, and also be sure to install the protrusions and
the valve stopper so that they are aligned in a straight line.
16. Reinstall any removed parts in reverse order of removal.
IWhen installing intake manifold, injector tube and intake
manifold collectors, refer to EM-12, ªTIGHTENING PROCE-
DURESº.
IAfter installation, run engine for a few minutes, and check
for leaks.
IBe careful not to spill coolant over engine compartment.
Use a rag to absorb coolant.
SLC252B
INSPECTIONNBLC00331. Check valve seating condition at ordinary room temperatures.
It should seat tightly.
2. Check valve opening temperature and maximum valve lift.
Standard
Valve opening temperature 95ÉC (203ÉF)
Valve lift More than 8.0 mm/108ÉC
(0.315 in/226ÉF)
3. Then check if valve closes at 5ÉC (9ÉF) below valve opening
temperature.
ENGINE COOLING SYSTEM
Water Control Valve (Cont'd)
LC-18

Radiator
REMOVAL AND INSTALLATION=NBLC00231. Remove under cover.
2. Remove suspension member stay.
3. Drain coolant from radiator.
4. Disconnect radiator upper and lower hoses.
5. Remove upper and lower radiator shroud.
6. Remove A/T oil cooler hoses.
7. Disconnect reservoir tank hose.
8. Remove radiator mounting bracket.
9. Remove radiator.
10. After repairing or replacing radiator, install any part removed in reverse order of removal.
When filling radiator with coolant, refer to MA-14, ªChanging Engine Coolantº.
SLC331B
GI
MA
EM
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ENGINE COOLING SYSTEM
Radiator
LC-19