Infiniti FX35 / FX45. Manual - part 624

NOISE, VIBRATION AND HARSHNESS (NVH) TROUBLESHOOTING

EM-13

< SERVICE INFORMATION >

[VQ35DE]

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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

C

A

—

A

B

—

Tappet 
noise

Valve clearance

EM-91

Rattle

C

A

—

A

B

C

Camshaft 
bearing 
noise

Camshaft runout
Camshaft journal oil 
clearance

EM-84
EM-84

Crank-
shaft pul-
ley
Cylinder 
block 
(Side of 
engine)
Oil pan

Slap or 
knock

—

A

—

B

B

—

Piston pin 
noise

Piston to piston pin oil  
clearance
Connecting rod bushing 
oil clearance

EM-138

EM-138

Slap or 
rap

A

—

—

B

B

A

Piston 
slap noise

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

EM-138

EM-138

EM-138
EM-138

Knock

A

B

C

B

B

B

Connect-
ing rod 
bearing 
noise

Connecting rod bushing 
oil clearance
Connecting rod bearing 
oil clearance 

EM-138

EM-138

Knock

A

B

—

A

B

C

Main bear-
ing noise

Main bearing oil clear-
ance
Crankshaft runout

EM-138

EM-138

Front of 
engine
Timing 
chain case

Tapping or 
ticking

A

A

—

B

B

B

Timing 
chain and 
timing 
chain ten-
sioner 
noise

Timing chain cracks 
and wear
Timing chain tensioner 
operation

EM-65

EM-64

Front of 
engine

Squeak-
ing or fizz-
ing

A

B

—

B

—

C

Drive belts 
(Sticking 
or slip-
ping)

Drive belts deflection

EM-14

Creaking

A

B

A

B

A

B

Drive belts 
(Slipping)

Idler pulley bearing op-
eration

Squall
Creak

A

B

—

B

A

B

Water 
pump 
noise

Water pump operation

CO-22

EM-14

< SERVICE INFORMATION >

[VQ35DE]

DRIVE BELTS

DRIVE BELTS

Checking Drive Belts

INFOID:0000000001429496

WARNING:

Be sure to perform when engine is stopped.
1.

Inspect belts for cracks, fraying, wear and oil. If necessary, replace.

2.

Inspect drive belt deflection or tension at a point on belt midway
between pulleys.

• Inspection should be done only when engine is cold, or over

30 minutes after engine is stopped.

• Measure the belt tension with belt tension gauge (Commercial

service tool: BT3373-F or equivalent) (A) at points marked 
shown in the figure.

• When measuring the deflection, apply 98 N (10 kg, 22 lb) at

the   marked point.

• Adjust if the belt deflection exceeds the limit or if the belt ten-

sion is not within specifications.

CAUTION:

• When checking the belt deflection or the tension immedi-

ately after installation, first adjust it to the specified value.
Then, after turning crankshaft two turns or more, re-adjust
to the specified value to avoid variation in deflection
between pulleys.

• Tighten idler pulley lock nut by hand and measure the deflection or the tension without loose-

ness.

Belt Deflection and Tension

*: If belt tension gauge cannot be installed at check points shown, check drive belt tension at different location on belt.

Tension Adjustment

INFOID:0000000001429497

CAUTION:

1 : Power steering oil pump

2 :  Alternator

3 : Idler pulley

4 : Crankshaft pulley

5 :  A/C  compressor

JPBIA0421ZZ

JPBIA0422ZZ

Items

Deflection adjustment

Unit: mm (in)

Tension adjustment*

Unit: N (kg, lb)

Used belt

New belt

Used belt

New belt

Limit

After adjustment

Limit

After adjustment

Alternator and 
power steering 
oil pump belt

12 (0.47)

7 - 8

(0.28 - 0.31)

6 - 7

(0.24 - 0.28)

294 (30, 66)

730 - 818

(74.5 - 83.4,

164 - 184)

838 - 926

(85.5 - 94.5,

188 - 208)

A/C compressor 
belt

12 (0.47)

9 - 10

(0.35 - 0.39)

8 - 9

(0.31 - 0.35)

196 (20, 44)

348 - 436

(35.5 - 44.5,

78 - 98)

470 - 559

(47.9 - 57.0,

106 - 126)

Applied pushing 
force

98 N (10 kg, 22 lb)

—

Portion

Belt tightening method for adjustment

Alternator and power steering oil pump belt

Adjusting bolt on idler pulley

A/C compressor belt

Adjusting bolt on idler pulley

DRIVE BELTS

EM-15

< SERVICE INFORMATION >

[VQ35DE]

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• When belt is replaced with a new one, adjust it to value for “New belt” to accommodate for insuffi-

cient adaptability with pulley grooves.

• When deflection or tension of belt being used exceeds “Limit”, adjust it to value for “After adjust-

ment”.

• When checking belt deflection or tension immediately after installation, first adjust it to the specified

value. Then, after turning crankshaft two turns or more, re-adjust to the specified value to avoid vari-
ation in deflection between pulleys.

• When installing belt, make sure that it is correctly engaged with pulley grooves.
• Keep engine oil, working fluid and engine coolant away from belt and pulley grooves.
• Do not twist or bend belt excessively.

ALTERNATOR AND POWER STEERING OIL PUMP BELT

1.

Remove front engine undercover with power tool.

2.

Loosen idler pulley lock nut (A) and adjust tension by turning
adjusting bolt (B).
• For the specified belt tension, refer to 

EM-14, "Checking Drive

Belts"

.

3.

Tighten nut (A).

A/C COMPRESSOR BELT

1.

Remove front engine undercover with power tool.

2.

Loosen idler pulley lock nut (C) and adjust tension by turning adjusting bolt (D).
• For the specified belt tension, refer to 

EM-14, "Checking Drive Belts"

.

3.

Tighten nut (C).

Removal and Installation

INFOID:0000000001429498

REMOVAL

1.

Remove front engine undercover with power tool.

2.

Remove alternator and power steering oil pump belt. Refer to 

EM-14, "Tension Adjustment"

.

3.

Remove A/C compressor belt. Refer to 

EM-14, "Tension Adjustment"

.

CAUTION:

Grease is applied to idler pulley adjusting bolt. Be careful to keep grease away from belt.

INSTALLATION

1.

Install belts to pulley in reverse order of removal.

CAUTION:

• Make sure drive belt is correctly engaged with pulley groove.
• Make sure that for engine oil and engine coolant do not adhere to belt and each pulley grooves.

1 : Alternator and power steering oil pump belt

2 : A/C compressor belt

3 : Power steering oil pump

4 : Idler pulley

5 : Alternator

6 : Crankshaft pulley

7 :  A/C  compressor

 

 : 34.8 N·m (3.5 kg-m, 26 ft-lb)

JPBIA0423ZZ

 

 : 34.8 N·m (3.5 kg-m, 26 ft-lb)

EM-16

< SERVICE INFORMATION >

[VQ35DE]

DRIVE BELTS

2.

Adjust belt tension. Refer to 

EM-14, "Tension Adjustment"

.

3.

Tighten each adjusting bolt and nut to the specified torque.

4.

Make sure that tension of each belt is within the standard. Refer to 

EM-14, "Checking Drive Belts"

.