Lexus SC300 / Lexus SC400. Manual - part 348

EG0EY–02

DRIVE BELT INSPECTION

INSPECT DRIVE BELT
HINT: A belt tensioner is used, so checking the belt tension
is not necessary.

(a)  Visually check the belt for excessive wear, frayed cords etc.

If necessary, replace the drive belt.
HINT:

•

Cracks on the rib side of a belt are considered
acceptable. If the drive belt has chunks missing from the
ribs, it should be replaced.

•

The drive belt tension can be released by turning the the
belt tensioner counterclockwise. The pulley bolt for the
belt tensioner has a left–hand thread.

(b)  Check the belt tensioner operation.

•

Check that the belt tensioner moves downward when
the drive belt is pressed down at the points indicated in
the illustration with approx. 98 N (10 kgf, 22.0 lbf) of
force.

•

Check the alignment of the belt tensioner pulley to make
sure the drive belt will not slip off the pulley.

If necessary, replace the belt tensioner.

•

Check that the arrow mark on the belt tensioner falls
within area A of the scale.

If it is outside area A, replace the drive belt.
HINT:

•

When a new belt is installed, it should lie within area B.
If not, the drive belt is not correct.

•

After installing a belt, check that it fits properly in the
ribbed grooves.

•

Check by hand to confirm that the belt has not slipped
out of the groove on the bottom of the pulley.

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1UZ–FE ENGINE

ENGINE MECHANICAL

EG–13

EG21S–02

VALVE CLEARANCE INSPECTION AND
ADJUSTMENT

HINT: Inspect and adjust the valve clearance when the en-
gine is cold.

1.  DISCONNECT NEGATIVE TERMINAL CABLE FROM

BATTERY
CAUTION: Work must be started after 90 seconds from
the time the ignition switch is turned to the “LOCK” posi-
tion and the negative (–) terminal cable is disconnected
from the battery.

2. 

DRAIN ENGINE COOLANT

3. 

REMOVE THROTTLE BODY COVER

(a)  Disconnect the EVAP hose from the hose clamp.
(b)  Remove the cap nut.
(c)  Loosen the 2 bolts, and remove the hose clamp and throttle

body cover.

4. 

DISCONNECT CONTROL CABLES TO THROTTLE BODY
Disconnect the following cables:
(1) Accelerator 

cable

(2)  Transmission throttle control cable
(3)  Cruise control actuator cable

5. 

REMOVE INTAKE AIR CONNECTOR

(a)  Disconnect the following hoses:

(1)  Air hose from IAC valve
(2) Air 

hose (from air control valve on PS pump) from intake

air connector

EG–14

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1UZ–FE ENGINE

ENGINE MECHANICAL

(b)  Remove the bolt holding the intake air connector to the

cylinder head cover.

(c)  Remove the 2 hose clamps.
(d)  Disconnect the intake air connector from the throttle body

and air cleaner hose, and remove the intake air connector.

6. 

REMOVE UPPER HIGH–TENSION CORD COVER

(a)  Remove the 2 bolts.
(b) Disconnect 

the front side claw groove of the upper cord cover

from the claw of lower cord cover, and remove the upper cord
cover.

7. 

REMOVE RH ENGINE WIRE COVER
Remove the bolt and engine wire cover.

8. 

REMOVE LH ENGINE WIRE COVER
Remove the 2 bolts and engine wire cover.

9. 

REMOVE VSV FOR EVAP SYSTEM
Remove the 2 bolts, and disconnect the VSV from the cylin-
der head cover and timing belt cover.

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1UZ–FE ENGINE

ENGINE MECHANICAL

EG–15

10.  REMOVE RH NO.3 TIMING BELT COVER

Remove the 3 bolts, timing belt cover and 3 gaskets.

11.  DISCONNECT FUEL INLET HOSE FROM LH DELIVERY

PIPE
Remove the pulsation damper and 2 gaskets, and discon-
nect the fuel inlet hose from the delivery pipe.

CAUTION:

•

Put a shop towel under the delivery pipe.

•

Slowly loosen the union bolt.

12. DISCONNECT FUEL RETURN HOSE FROM FUEL

RETURN PIPE

13.  DISCONNECT PCV HOSE FROM LH CYLINDER HEAD
14.  REMOVE LH NO.3 TIMING BELT COVER
(a)  Remove the 4 bolts.
(b)  Disconnect the cord grommet from the timing belt cover, and

remove the timing belt cover and 3 gaskets.

(c)  Remove the cord grommet from the high–tension cord.

15.  DISCONNECT HEATER WATER VALVE FROM BODY
(a)  Disconnect the VSV connector.
(b)  Remove the bolt holding the engine wire clamp to the water

valve bracket.

(c)  Remove the 2 bolts, and disconnect the water valve and

bracket assembly.

16.  REMOVE THROTTLE BODY
(a)  Disconnect the following connectors:

(1)  Throttle position sensor connector
(2) w/ 

TRAC:

Sub–throttle position sensor connector
(3) w/ 

TRAC:

Sub–throttle actuator connector

EG–16

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1UZ–FE ENGINE

ENGINE MECHANICAL