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