Infiniti FX35, FX50 (S51). Manual - part 976

EM-204

< UNIT DISASSEMBLY AND ASSEMBLY >

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ENGINE UNIT

ENGINE UNIT

Disassembly

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1.

Remove intake manifold. Refer to 

EM-179, "Exploded View"

.

2.

Remove exhaust manifold. Refer to 

EM-205, "Exploded View"

.

3.

Remove oil pan (lower). Refer to 

EM-188, "Exploded View"

.

4.

Remove ignition coil, spark plug and rocker cover. Refer to 

EM-191, "Exploded View"

.

5.

Remove timing chain. Refer to 

EM-212, "Exploded View"

.

6.

Remove camshaft (EXH) and VVEL ladder assembly. Refer to 

EM-227, "Exploded View"

.

7.

Remove cylinder head. Refer to 

EM-245, "Exploded View"

.

Assembly

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Assemble in the reverse order of disassembly.

EXHAUST MANIFOLD AND THREE WAY CATALYST

EM-205

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EXHAUST MANIFOLD AND THREE WAY CATALYST

Exploded View

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Disassembly and Assembly

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DISASSEMBLY

1.

Remove heated oxygen sensor 2.

CAUTION:

Heated oxygen sensor 2 is not reusable. Never remove heated oxygen sensor 2 unless this is
required.

1.

Exhaust manifold cover (bank 2)

2.

Exhaust manifold (bank 2)

3.

Gasket

4.

Exhaust manifold (bank 1)

5.

Exhaust manifold cover (bank 1)

6.

Gasket

7.

Three way catalyst (bank 1)

8.

Heated oxygen sensor 2 (bank 1)

9.

Air fuel ratio sensor 1 (bank 1)

10. Three way catalyst (bank 2)

11. Heated oxygen sensor 2 (bank 2)

12.

Air fuel ratio sensor 1 (bank 2)

13. Harness bracket 

A.

To cylinder head (bank 2)

B.

To exhaust front tube

Refer to 

GI-4, "Components"

 for symbols in the figure.

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EM-206

< UNIT DISASSEMBLY AND ASSEMBLY >

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EXHAUST MANIFOLD AND THREE WAY CATALYST

• Using the heated oxygen sensor wrench [SST: KV10114400

(J-38365)] (A), remove heated oxygen sensor 2 (1).
NOTE:
• The heated oxygen sensor 2 is removable under vehicle-

mounted condition.

• The figure shows an example of bank 1.

2.

Remove three way catalyst (bank 1 and bank 2).

3.

Remove air fuel ratio sensor 1as per the following:

CAUTION:

Air fuel ratio sensor 1 is not reusable. Never remove air fuel ratio sensor 1 unless this is required.
• Using the heated oxygen sensor wrench [SST: KV10114400 (J-38365)], remove air fuel ratio sensor 1.

NOTE:
The air fuel ration sensor 1 is removable under vehicle-mounted condition.

4.

Remove exhaust manifold.
• Loosen nuts in the reverse order of figure to remove exhaust

manifold with power tool.

NOTE:
Disregard No. 9 to No. 12 when loosening.

5.

Remove exhaust manifold gaskets.

CAUTION:

Cover engine openings to avoid entry of foreign materials.

ASSEMBLY

Note the following item, and install in the reverse order of removal.

Exhaust Manifold Gasket

• Install exhaust manifold gasket in directional shown in the figure.

Exhaust Manifold

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A 

: Bank 1

B 

: Bank 2

: Engine front

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A

: Triangle press

: Above

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EXHAUST MANIFOLD AND THREE WAY CATALYST

EM-207

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• Tighten mounting nuts in numerical order as shown in the figure.

NOTE:
Tighten mounting nuts No. 1 to 4 in two steps. The numerical order
No. 9 to 12 shown second steps.

Air Fuel Ratio Sensor 1, Heated Oxygen Sensor 2

CAUTION:

• Before installing a new sensors, clean exhaust system threads using oxygen sensor thread cleaner

(commercial service tool: J-43897-18 or J-43897-12), and apply anti-seize lubricant (commercial ser-
vice tool).

•  Sensors are not reusable. Replace them with a new one after removal. When replacing them, handle

with care not to impact on them.

•  When installing the new sensors, set the heated oxygen sen-

sor wrench [SST: KV10114400(J-38365)] (A) in the hexagonal
part to tighten the them.

• Never over torque sensors. Doing so may cause damage to the sensors, resulting in “MIL” coming

on.

Inspection

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INSPECTION AFTER DISASSEMBLY

Surface Distortion

• Check the surface distortion of the exhaust manifold mating sur-

face with a straightedge (A) and a feeler gauge (B).

• If it exceeds the limit, replace exhaust manifold.

A

:  Bank  1

B

:  Bank  2

: Engine front

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: Heated oxygen sensor 2 (bank 1)

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Limit

: Refer to 

EM-283, "Exhaust Manifold"

.

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