2011 INFINITI QX56 engine

PREPARATIONEM-9
< PREPARATION >
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Commercial Service ToolINFOID:0000000006289519
KV101197S0
(—)
Injector seal drift set
Installing fuel injector seal ring
EG15050500
(J-45402)
Compression gauge adapter Checking compresion pressure
Tool number
(Kent-Moore No.)
Tool name
Description
JPBIA3281ZZ
ZZA1225D
(Kent-Moore No.)
Tool name
Description
(—)
Tube presser Pressing the tube of liquid gasket
(—)
Power tool Loosening nuts and bolts
(—)
Spark plug wrench Removing and installing spark plug
a: 14 mm (0.55 in)
(—)
Manual lift table caddy Removing and installing engine
S-NT052
PBIC0190E
JPBIA0399ZZ
ZZA1210D
Revision: 2010 May2011 QX56

CAMSHAFT VALVE CLEARANCEEM-13
< BASIC INSPECTION >
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a. Set No. 1 cylinder at TDC of its compression stroke.
 Rotate crankshaft pulley clockwise to align timing mark
(grooved line without color) (B) with timing indicator (A).
 Check that exhaust cam nose on No. 1 cylinder (engine front side of bank 1) is located as shown in the figure.
 If not, turn crankshaft one revolution (360 degrees) and align as shown in the figure.
 By referring to the figure, measure the valve clearances at locations marked “ ×” as shown in the table below (locations
indicated in the figure).
 No. 1 cylinder at compression TDC
NOTE:
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1 : Exhaust camshaft (bank 1) : Engine front
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: Engine front
Measuring position [bank 2 (A)] No. 2
CYL. No. 4
CYL. No. 6
CYL. No. 8
CYL.
No. 1 cylinder at com- pression TDC EXH
× (C)
INT × (D) × (E)
Measuring position [bank 1 (B)] No. 1
CYL. No. 3
CYL. No. 5
CYL. No. 7
CYL.
No. 1 cylinder at com- pression TDC INT
× (F) × (G)
EXH × (H) × (I)
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Revision: 2010 May2011 QX56

EM-14
< BASIC INSPECTION >
CAMSHAFT VALVE CLEARANCE
To measure valve clearance of No. 1 cylinder INT valve (front
side), insert feeler gauge (A) (commercial service tool) as shown
in the figure.
b. Rotate crankshaft 270 degrees clockwise (when viewed from engine front) to align No. 3 cylinder at TDC its compression stroke.
NOTE:
Crankshaft pulley mounting bolt flange has an angle mark (B)
every 90 degrees (c). They can be used as a guide to rotation
angle.
 By referring to the figure, measure the valve clearances atlocations marked “ ×” as shown in the table below (locations
indicated in the figure).
 No. 3 cylinder at compression TDC
c. Rotate crankshaft 90 degrees clockwise (when viewed from engine front) to align No. 6 cylinder at TDC of compression stroke.
NOTE:
: Engine front
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A : Paint mark
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: Engine front
Measuring position [bank 2 (A)] No. 2
CYL. No. 4
CYL. No. 6
CYL. No. 8
CYL.
No. 3 cylinder at com- pression TDC EXH
× (C)
INT × (D)
Measuring position [bank 1 (B)] No. 1
CYL. No. 3
CYL. No. 5
CYL. No. 7
CYL.
No. 3 cylinder at com- pression TDC INT
× (E) × (F)
EXH × (G) × (H)
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Revision: 2010 May2011 QX56

CAMSHAFT VALVE CLEARANCEEM-15
< BASIC INSPECTION >
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Crankshaft pulley mounting bolt flange has an angle mark (B)
every 90 degrees (c). They can be used as a guide to rotation
angle.
 By referring to the figure, measure the valve clearances at
locations marked “ ×” as shown in the table below (locations
indicated in the figure).
 No. 6 cylinder at compression TDC
5. Perform adjustment or repl acement if the measured value is out of the standard.
 If a valve clearance on the exhaust side is out of s pecification, adjust the valve clearance. Refer to EM-
77, "Inspection".
 If a valve clearance on the intake side is out of s pecification, replace VVEL ladder assembly & cylinder
head assembly. Refer to EM-86, "
Exploded View".
CAUTION:
Never adjust valve clearance on the intake side.
NOTE:
Since the valve lifter (INT) cannot be replaced by the piece, VVEL ladder assembly & cylinder head
assembly replacement are required.
A : Paint mark
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: Engine front
Measuring position [bank 2 (A)] No. 2
CYL. No. 4
CYL. No. 6
CYL. No. 8
CYL.
No. 6 cylinder at com- pression TDC EXH
× (B) × (C)
INT × (D)
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Revision: 2010 May2011 QX56

EM-16
< BASIC INSPECTION >
COMPRESSION PRESSURE
COMPRESSION PRESSURE
InspectionINFOID:0000000006289521
1. Warm up engine thoroughly. Then, stop it.
2. Release fuel pressure. Refer to EC-153, "
Work Procedure".
CAUTION:
If CONSULT-III is not used to release fuel pr essure leave the fuel pump fuse disconnected until
step 7.
3. Remove fuel pump fuse in IPDM E/R. NOTE:
 For the fuse number, refer to EC-114, "
Wiring Diagram".
 For the fuse arrangement, refer to PG-143, "
Fuse, Connector and Terminal Arrangement".
4. Remove engine cover. Refer to EM-25, "
Exploded View".
5. Remove ignition coil and spark plug from each cylinder. Refer to EM-29, "
Exploded View".
6. Connect engine tachometer (not required in use of CONSULT-III).
7. Install the compression tester with Tool [SST: EG15050500 (J- 45402)] into the spark plug hole.
8. Measure compression pressure using compressi on gauge connected with flexible type adapter (commer-
cial service tool).
9. With accelerator pedal fully depressed, turn ignition switch to “START” for cranking. When the gauge pointer stabilizes, read the compression pressure and the engine rpm. Perform these steps to check each
cylinder.
CAUTION:
 Measure a six-cylinder under the same conditio ns since a measurement depends on measure-
ment conditions (engine water temperature, etc.).
 Always use a fully changed battery to obtain the specified engine speed.
 If the engine speed is out of the specified range, c heck battery liquid for proper gravity. Check the
engine speed again with normal battery gravity. Refer to PG-159, "
How to Handle Battery".
 If compression pressure is below the minimum value, check valve clearances and parts associated with combustion chamber (valve, valve seat, piston, pi ston ring, cylinder bore, cylinder head, cylinder head
gasket). After checking, measure compression pressure again.
 If a cylinder has low compression pressure, pour a small amount of engine oil into the spark plug hole of the cylinder to re-check it for compression.
- If the added engine oil improves the compression, pi ston rings may be worn out or damaged. Check pis-
ton rings and replace if necessary. Refer to EM-107, "
Disassembly and Assembly".
- If the compression pressure remains at low level despite the addition of engine oil, valves may be mal- functioning. Check valves for damage. Replace valve or valve seat accordingly. Refer to EM-107, "
Dis-
assembly and Assembly".
 If two adjacent cylinders have respectively low co mpression pressure and their compression remains
low even after the addition of engine oil, cylinder head gaskets are leaking. In such a case, replace cyl-
inder head gaskets. Refer to EM-87, "
Removal and Installation".
10. After inspection is completed, install removed parts.
11. Start the engine, and check that the engine runs smoothly.
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Compression pressure : Refer to EM-132, "GeneralSpecification".
Revision: 2010 May2011 QX56

EM-18
< SYMPTOM DIAGNOSIS >
NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTING
SYMPTOM DIAGNOSIS
NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTING
NVH Troubleshooting - Engine NoiseINFOID:0000000006289522
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Revision: 2010 May2011 QX56

NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTINGEM-19
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Use the Chart Below to Help You Find the Cause of the SymptomINFOID:0000000006289523
1. Locate the area where noise occurs.
2. Confirm the type of noise.
3. Specify the operating condition of the engine.
4. Check specified noise source.
If necessary, repair or replace these parts.
A: Closely related B: Related C: Sometimes related —: Not related Location
of noise Type of
noise Operating condition of engine
Source of noise Check item Refer-
ence page
Before
warm- up After
warm- up When
start- ing When
idling When
racing While
driving
Top of en-
gine
Rocker
cover
Cylinder
head Ticking or
clicking
CA—AB— Tappet
noiseValve clearance
EM-12
Rattle C A — A B C Camshaft
bearing
noiseCamshaft runout
Camshaft journal oil
clearance
EM-77
Crank-
shaft pul-
ley
Cylinder
block
(Side of
engine)
Oil panSlap or
knock
—A—B B—
Piston pin
noisePiston to piston pin oil
clearance
Connecting rod bushing
oil clearance
EM-115
Slap or
rap
A——B B A
Piston
slap noisePiston to cylinder bore
clearance
Piston ring side clear-
ance
Piston ring end gap
Connecting rod bend
and torsion
EM-115
Knock A B C B B B
Connect-
ing rod
bearing
noiseConnecting rod bushing
oil clearance
Connecting rod bearing
oil clearance
EM-115
Knock A B — A B C
Main bear-
ing noiseMain bearing oil clear-
ance
Crankshaft runout
EM-115
Front of
engine
Timing
chain caseTapping or
ticking
AA—BBB Timing
chain and
timing
chain ten-
sioner
noiseTiming chain cracks
and wears
Timing chain tensioner
operation
EM-72
Front of
engineSqueak-
ing or fizz-
ing
AB—B—C Drive belts
(Sticking
or slip-
ping)Drive belts deflection
EM-20
CreakingABABAB Drive belts
(Slipping)Idler pulley bearing op-
eration
Squall
Creak AB—BAB Water
pump
noiseWater pump operation
CO-19
Revision: 2010 May2011 QX56

EM-20
< PERIODIC MAINTENANCE >
DRIVE BELTS
PERIODIC MAINTENANCE
DRIVE BELTS
Exploded ViewINFOID:0000000006289524
CheckingINFOID:0000000006289525
WARNING:
Be sure to perform the these steps when engine is stopped.
 Check that the indicator (C) (notch on fixed side) of each auto-tensioner is within the possible use range (A).
NOTE:
 Check the each auto-tensioners indication when the engine is cold.
 When new drive belts is installed, the indicator (notch on fixed side) should be within the range (B) in the\
figure.
 Visually check all drive belts for wear, damage or cracks.
 If the indicator (notch on fixed side) is out of the possible use range or drive belts are damaged, replace drive
belts.
Tension AdjustmentINFOID:0000000006289526
Refer to EM-132, "Drive Belts".
Removal and InstallationINFOID:0000000006289527
REMOVAL
1. Move reservoir tank to the position without the hindrance for work. Refer to CO-13, "Exploded View".
1. Drive belt 2. Power steering oil pump pulley 3. Alternator pulley
4. Crankshaft pulley 5. A/C compressor 6. Idler pulley
7. Cooling fan pulley 8. Water pump pulley 9. Drive belt auto-tensioner
A. Possible use range B. Range when new drive belt is in-
stalledC. Indicator
D. View D
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Revision: 2010 May2011 QX56