Lexus RX300 (MCU15). Manual - part 442

Z09167

Cylinder head side:

Air intake chamber side:

A05242

RH side:

LH side:

P12496

EM–52

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ENGINE MECHANICAL

CYLINDER HEAD

LEXUS RX300   (RM785E)

24.

INSPECT INTAKE MANIFOLD

Using a precision straight edge and feeler gauge, measure the
surface contacting the cylinder head and air intake chamber for
warpage.

Maximum warpage: 
Air intake chamber side: 0.15 mm (0.0059 in.) 
Cylinder head side: 0.08 mm (0.0031 in.)

If warpage is greater than maximum, replace the manifold.

25.

INSPECT EXHAUST MANIFOLDS

Using a precision straight edge and feeler gauge, measure the
surface contacting the cylinder head for warpage.

Maximum warpage: 0.50 mm (0.0196 in.)

If warpage is greater than maximum, replace the manifold.

26.

INSPECT 12 POINTED HEAD CYLINDER HEAD
BOLTS

Using vernier calipers, measure the tension portion diameter of
the bolt.

Standard outside diameter: 
8.95 – 9.05 mm (0.3524 – 0.3563 in.)
Minimum outside diameter: 8.75 mm (0.3445 in.)

If the diameter is less than minimum, replace the bolt.

EM0KK–01

A05234

80 – 100

°C

P12803

SST

P12956

Bushing bore diameter

mm (in.)

10.295 – 10.313

(0.4053 – 0.4060)

10.345 – 10.363

(0.4073 – 0.4080)

Bushing size

Use STD

Use O/S 0.05

Both intake and exhaust

P11510

Intake

Exhaust

34.5 mm

(1.358 in.)

40.5 mm

(1.594 in.)

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ENGINE MECHANICAL

CYLINDER HEAD

EM–53

LEXUS RX300   (RM785E)

REPLACEMENT

1.

REPLACE VALVE GUIDE BUSHINGS

(a)

Gradually heat the cylinder head to 80 – 100

°C (176 –

212

°F).

(b)

Using SST and a hammer, tap out the guide bushing.
SST

09201–01055, 09950–70010 (09951–07100)

(c)

Using a caliper gauge, measure the bushing bore diame-
ter of the cylinder head.

(d)

Select a new guide bushing (STD or O/S 0.05).

If the bushing bore diameter of the cylinder head is greater than
10.313 mm (0.4060 in.), machine the bushing bore to the fol-
lowing dimension:

10.345 – 10.363 mm (0.4073 – 0.4080 in.)

If the bushing bore diameter of the cylinder head is greater than
10.363 mm (0.4080 in.), replace the cylinder head.

HINT:
Different bushings are used for the intake and exhaust.
(e)

Gradually heat the cylinder head to 80 – 100

°C (176 –

212

°F).

P12802

SST

Z09124

A05739

A05740

EM–54

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ENGINE MECHANICAL

CYLINDER HEAD

LEXUS RX300   (RM785E)

(f)

Using SST and a hammer, tap in a new guide bushing to
the specified protrusion height.
SST

09201–01055, 09950–70010 (09951–07100)

Protrusion height:
Intake: 11.1 – 11.5 mm (0.437 – 0.453 in.)
Exhaust: 8.9 – 9.3 mm (0.350 – 0.366 in.)

(g)

Using a sharp 5.5 mm reamer, ream the guide bushing to
obtain the standard specified clearance (See page
EM–43) between the guide bushing and valve stem.

2.

REPLACE CAMSHAFT TIMING GEAR (VVT–i)

NOTICE:
Do not remove or install the camshaft timing gear (VVT–i)
beside changing VVT–i or the camshaft.
(a)

Mount the hexagon wrench head portion of the camshaft
in a vise.

NOTICE:
Be careful not to damage the camshaft.

(b)

Using a 46 mm socket wrench, remove the lock nut by
turning it clockwise.

NOTICE:

S

Remove it under the condition that the lock pin is op-
erated and lock at the maximum delay angle position.

S

The lock nut have LH threads.

S

Never use any tool other than the socket wrench,
otherwise that may result in deforming the cam angle
rotor portion.

(c)

Remove the camshaft VVT–i.

HINT:
In case of having difficulty to remove VVT–i, apply a slight hit-
ting using a plastic–faced hammer and then remove it.
NOTICE:
Never remove the 3 bolts on the gear.

A05706

Align

A05738

A05245

A05243

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ENGINE MECHANICAL

CYLINDER HEAD

EM–55

LEXUS RX300   (RM785E)

(d)

Align the knock pin and knock pin groove and install VVT–
I on the camshaft.

NOTICE:
Install it under the condition that the lock pin is operated
and lock at the maximum delay angle position.

(e)

Apply the engine oil on the nut, the placing surface of
VVT–i and the screw portion.

HINT:
Be sure to apply the oil, otherwise the prescribed torque cannot
be obtained.
(f)

Using a 46 mm socket wrench, install and torque a new
lock nut by turning it counterclockwise.
Torque: 150 N·m (1,530 kgf·cm, 110 ft·lbf)

NOTICE:

S

Must change the nuts to the new ones when to change
VVT–i.

S

The lock nut have LH threads.

S

Never use any tool other than the socket wrench,
otherwise that may result in deforming the cam angle
rotor portion.

3.

REPLACE SPARK PLUG TUBE GASKETS

(a)

Bend up the tab on the ventilation baffle plate which pre-
vents the gasket from the slipping out.

(b)

Using a screwdriver and hammer, tap out the gasket.

(c)

Using needle–nose pliers, pry out the gasket.