Lexus LS400 (2000 year). Manual — part 87

A02868

Ground
Cable

Wire Protector

A02869

RH Cylinder Head

LH Cylinder Head

Front

1

9

10

8

7

6

5

4

3

2

1

3

5

10

8

2

4

6

9

7

A02872

RH Cylinder Head

LH Cylinder Head

A

A

–

ENGINE MECHANICAL

CYLINDER HEAD

EM–41

1223

(c)

Remove the bolt, and disconnect the ground cable from
the LH cylinder head.

(d)

Remove the bolt, and disconnect the engine wire protec-
tor from the LH cylinder head.

(e)

Uniformly loosen the 10 cylinder head bolts on one side
of each cylinder head in several passes, in the sequence
shown, then do the other side as shown. Remove the 20
cylinder head bolts and plate washers.

NOTICE:

Cylinder head warpage or cracking could result from
removing bolts in incorrect order.

Do not drop the plate washer for cylinder head bolt
into portion A of the cylinder head. If dropped into
portion A, the plate washer will pass through the cyl-
inder head and cylinder block into the oil pan.

A02871

A02883

A02884

EM–42

–

ENGINE MECHANICAL

CYLINDER HEAD

1224

(f)

Lift the cylinder head from the dowels on the cylinder
block, and place the 2 cylinder heads on wooden blocks
on a bench.

HINT:
If the cylinder head is lift off, pry between the cylinder head and
cylinder block with a screwdriver.
NOTICE:

Be careful not to damage the contact surfaces of the
cylinder head and cylinder block.

The cylinder head should not be tilted so as to secure
the valve lifter. If the cylinder head is tilted, remove
the valve lifter and check that the adjusting shim is
set correctly.

26.

REMOVE RH EXHAUST MANIFOLD FROM CYLINDER
HEAD

(a)

Remove the 3 bolts and heat insulator.

(b)

Remove the 8 nuts, exhaust manifold and gasket.

27.

REMOVE LH EXHAUST MANIFOLD FROM CYLINDER
HEAD

(a)

Remove the 3 bolts and heat insulator.

(b)

Remove the 8 nuts, exhaust manifold and gasket.

EM09I–02

A02205

A02206

EM–4

–

ENGINE MECHANICAL

VALVE CLEARANCE

1186

VALVE CLEARANCE

INSPECTION

HINT:
Inspect and adjust the valve clearance when the engine is cold.
1.

DRAIN ENGINE COOLANT

2.

REMOVE BATTERY CLAMP COVER

3.

REMOVE AIR CLEANER INLET

4.

REMOVE V–BANK COVER

5.

REMOVE AIR CLEANER AND INTAKE AIR CONNEC-
TOR ASSEMBLY

6.

REMOVE NO.3 TIMING BELT COVERS
(See page

EM–15

)

7.

REMOVE IGNITION COILS (See page

IG–7

)

8.

REMOVE RH CYLINDER HEAD COVER

Remove the 9 bolts, 9 seal washers and cylinder head cover.
9.

REMOVE LH CYLINDER HEAD COVER

(a)

Remove the oil dipstick for the transmission.

(b)

Disconnect the PCV hose.

(c)

Disconnect the engine wire clamp from the wire bracket
on the delivery pipe.

(d)

Remove the 9 bolts, 9 seal washers and cylinder head
cover.

10.

SET NO.1 CYLINDER TO TDC/COMPRESSION

(a)

Turn the crankshaft pulley, and align its groove with timing
mark ”0” of the No.1 timing belt cover.

(b)

Check that the timing marks of the camshaft timing pul-
leys and timing belt rear plates are aligned.

If not, turn the crankshaft 1 revolution (360

°

) and align the mark

as above.

A02207
A02208

A02209

RH Cylinder Head

LH Cylinder Head

Front

A02210
A02211

A02212

RH Cylinder Head

LH Cylinder Head

Front

A02213

–

ENGINE MECHANICAL

VALVE CLEARANCE

EM–5

1187

11.

INSPECT VALVE CLEARANCE

(a)

Check only the valves indicated.

Using a feeler gauge, measure the clearance be-
tween the valve lifter and camshaft.

Record the out–of–specification valve clearance
measurements. They will be used later to determine
the required replacement adjusting shim.

Valve clearance (Cold):

Intake

0.15 – 0.25 mm (0.006 – 0.010 in.)

Exhaust

0.25 – 0.35 mm (0.010 – 0.014 in.)

(b)

Turn the crankshaft 1 revolution (360

°

) and align the mark

as above. (See procedure in step 10)

(c)

Check only the valves indicated as shown. Measure the
valve clearance. (See procedure in step (a))

12.

ADJUST VALVE CLEARANCE

(a)

Remove the timing belt. (See page

EM–15

)

(b)

Remove the camshafts. (See page

EM–34

)

(c)

Remove the valve lifter and adjusting shim.

(d)

Determine the replacement adjusting shim size according
to these Formula or Charts:

Using a micrometer, measure the thickness of the
removed shim.

Calculate the thickness of a new shim so that the
valve clearance comes within the specified value.
T . . ... Thickness of removed shim
A . . ... Measured valve clearance
N . . ... Thickness of new shim