Infiniti QX56 (JA60). Manual - part 464

EM-10

< FUNCTION DIAGNOSIS >

NOISE, VIBRATION, AND HARSHNESS (NVH) TROUBLESHOOTING

FUNCTION DIAGNOSIS

NOISE, VIBRATION, AND HARSHNESS (NVH) TROUBLESHOOTING

NVH Troubleshooting - Engine Noise

INFOID:0000000005148972

AWBIA0149ZZ

NOISE, VIBRATION, AND HARSHNESS (NVH) TROUBLESHOOTING

EM-11

< FUNCTION DIAGNOSIS >

C

D

E

F

G

H

I

J

K

L

M

A

EM

N

P

O

Use the Chart Below to Help You Find the Cause of the Symptom

INFOID:0000000005148973

1. Locate the area where noise occurs.
2. Confirm the type of noise.
3. Specify the operating condition of engine.
4. Check specified noise source.
If necessary, repair or replace these parts.

1.

Timing chain

2.

Intake valve

3.

Exhaust valve

4.

Drive belt

5.

Water pump

A.

VTC noise

B.

Tappet noise

C.

Camshaft bearing noise

D.

Valve mechanism

E.

Rotation mechanism

F.

Piston pin noise

G.

Piston slap noise

H.

Main bearing noise

I.

Connecting rod bearing noise

J.

Drive belt noise (slipping)

K.

Drive belt noise (stick/slipping)

L.

Water pump noise

M.

Timing chain and chain tensioner noise

Location of 

noise

Type of 

noise

Operating condition of engine

Source of 

noise

Check item

Refer-

ence page

Be-

fore 

warm-

up

After 

warm-

up

When 

start-

ing

When 

idling

When 

racing

While 

driv-

ing

Top of en-
gine
Rocker cov-
er
Cylinder 
head

Ticking or 
clicking

C

A

—

A

B

—

Tappet noise

Valve clearance

EM-18

Rattle

C

A

—

A

B

C

Camshaft 
bearing noise

Camshaft journal clear-
ance
Camshaft runout

EM-53
EM-53

Crankshaft 
pulley
Cylinder 
block (Side 
of engine)
Oil pan

Slap or 
knock

—

A

—

B

B

—

Piston pin 
noise

Piston and piston pin 
clearance
Connecting rod bushing 
clearance

EM-90
EM-90

Slap or 
rap

A

—

—

B

B

A

Piston slap 
noise

Piston-to-bore clear-
ance
Piston ring side clear-
ance
Piston ring end gap
Connecting rod bend 
and torsion

EM-90
EM-90
EM-90
EM-90

Knock

A

B

C

B

B

B

Connecting 
rod bearing 
noise

Connecting rod bushing 
oil clearance (Small 
end)
Connecting rod bearing 
clearance (Big end)

EM-90
EM-90

Knock

A

B

—

A

B

C

Main bearing 
noise

Main bearing oil clear-
ance
Crankshaft runout

EM-90
EM-90

Front of en-
gine
Chain case 
cover
Front cover

Tapping 
or ticking

A

A

—

B

B

B

Timing chain 
and chain 
tensioner 
noise

Timing chain cracks 
and wear
Timing chain tensioner 
operation

EM-45
EM-45

EM-12

< FUNCTION DIAGNOSIS >

NOISE, VIBRATION, AND HARSHNESS (NVH) TROUBLESHOOTING

A: Closely related B: Related C: Sometimes related —: Not related

Front of en-
gine

Squeak-
ing or 
fizzing

A

B

—

B

—

C

Drive belts 
(Sticking or 
slipping)

Drive belts deflection

EM-13

Creaking

A

B

A

B

A

B

Drive belts 
(Slipping)

Idler pulley bearing op-
eration

Squall
Creaking

A

B

—

B

A

B

Water pump 
noise

Water pump operation

CO-20

Rattle

—

—

A

—

—

—

VTC

VTC lock pin clearance

EM-62

Location of 

noise

Type of 

noise

Operating condition of engine

Source of 

noise

Check item

Refer-

ence page

Be-

fore 

warm-

up

After 

warm-

up

When 

start-

ing

When 

idling

When 

racing

While 

driv-

ing

DRIVE BELTS

EM-13

< ON-VEHICLE MAINTENANCE >

C

D

E

F

G

H

I

J

K

L

M

A

EM

N

P

O

ON-VEHICLE MAINTENANCE

DRIVE BELTS

Exploded View

INFOID:0000000005148974

Checking Drive Belts

INFOID:0000000005148975

WARNING:

Be sure to perform when the engine is stopped.
1. Remove air duct and resonator assembly when inspecting drive belt.
2. Make sure that indicator (single line notch) of each auto tensioner is within the allowable working range

(between three line notches).

NOTE:

• Check the drive belt auto tensioner indication when the engine is cold.

• The indicator notch is located on the moving side of the drive belt auto tensioner. 

3. Visually check entire belt for wear, damage or cracks.
4. If the indicator is out of allowable working range or belt is damaged, replace the belt. Refer to 

EM-13

.

DRIVE BELT TENSION

There is no manual drive belt tension adjustment. The drive belt tension is automatically adjusted by the drive

belt auto tensioner.

Removal and Installation

INFOID:0000000005148976

REMOVAL

1. Remove the air duct and resonator assembly. Refer to 

EM-25, "Removal and Installation"

.

1.

Drive belt

2.

Power steering pump pulley

3.

Generator 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.

Allowable working range

LBIA0391E