LEXUS SC400 1991 Service Repair Manual

PREPARATION
SST (SPECIAL SERVICE TOOLS)
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ENGINE MECHANICAL PreparationEM±5
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SST (SPECIAL SERVICE TOOLS) (Cont'd)
RECOMMENDED TOOLS
EM±6±
ENGINE MECHANICAL Preparation
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EQUIPMENT
 


Part Name\
 
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Note
 Caliper gauge\
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HC/CO meter
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Compression gauge\
 
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Cylinder compression pressure
 Connecting rod aligner\
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Cylinder gauge
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Dial indicator
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Engine turn±up tester\
 
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 Feeler gauge\
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Micrometer
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Precision straight edge\
 
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 Spring tester\
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Valve spring
 


Steel square
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Valve spring
 


Torque wrench\
 
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 Vernier caliper\
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SSM (SPECIAL SERVICE MATERIALS)
 
Part Name
 
Part No.
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Use etc.  \
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Camshaft bearing cap  \
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Camshaft bearing ca
Cylinder head semi±circular plug 
Seal packing or equivalent
 
08826±00080
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Cylinder head semi±circular lug
Cylinder head cover Seal acking or equivalent 08826±00080\
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Cylinder head cover
Rear oil seal retainer  \
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Rear oil seal retainer
Oil pump  \
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Water inlet housing Seal packing 1282B,
Th b d 1282B i l t
 08826±00100\
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Water inlet housing
Water seal plate Three bond 1282B or equivalent 08826±00100\
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Water seal late
Water pump 

Adhesive 1324,
Three bond 1324 or equivalent
 

08833±00070
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Drive plate mounting bolt
 
Adhesive 1344,
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 Adhesive 1344,
Three bond 1344
,
 
08833±00080
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No.1 idler pulley mounting bolt Three bond 1344,
Loctite 242 or equivalent 08833±00080\
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No.1 idler ulley mounting bolt
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ENGINE MECHANICAL PreparationEM±7
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ENGINE TUNE±UP
INSPECTION OF ENGINE COOLANT
1. INSPECT ENGINE COOLANT LEVEL AT RESERVOIRTANK
The engine coolant level should be between the LOW and
FULL lines.
If low, check for leaks and add engine coolant up to the FULL
line.
2. INSPECT ENGINE COOLANT QUALITY There should not be any excessive deposits of rust or scales
around the radiator cap or reservoir tank filler hole, and the
engine coolant should be free from oil.
If excessively dirty, clean the engine coolant passages and
flush the cooling system.
INSPECTION OF ENGINE OIL
1. INSPECT ENGINE OIL QUALITYCheck the oil for deterioration, presence of water, discoloring
or thinning.
If the quality is poor, replace the oil.
Oil grade: API grade SG, Energy±Conserving II multi- grade. Recommended viscosity is as shown,
with SAE 5W±30 being the preferred engine
oil.
Drain and refill oil capacity:
w/ Oil filter change
4.8 liter (5.1 US qts, 4.2 lmp. qts)
w/o Oil filter change 4.5 liter (4.8 US qts, 4.0 lmp. qts)
2. INSPECT ENGINE OIL LEVELThe oil level should be between the ºLº and ºFº marks on the
dipstick.
If low, check for leakage and add oil up to ºFº mark.
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ENGINE MECHANICAL Engine Tune±UpEM±7
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INSPECTION OF BATTERY
1. INSPECT BATTERY SPECIFIC GRAVITY ANDELECTROLYTE LEVEL
(a) Check the specific gravity of each cell.
Standard specific gravity:
1.250±1.270 when fully charged at 20 5C (68 5F)
If not within specification, charge the battery.
(b) Check the electrolyte level of each cell.
If insufficient, refill with distilled (or purified) water.
2. CHECK BATTERY TERMINALS Check the battery terminals for looseness or corrosion.
INSPECTION AND CLEANING OF AIR
FILTER
1. REMOVE AIR FILTER(a) Open the air cleaner cap.
(b) Remove the air filter.
2. INSPECT AIR FILTER (a) Visually check that the air filter is not excessivelydamaged or oily.
(b) Clean the air filter with compressed air. First blow from the inside thoroughly, then blow off the outside of the air
filter.
3. REINSTALL AIR FILTER
EM±8
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ENGINE MECHANICAL Engine Tune±Up
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INSPECTION OF HIGH±TENSION CORDS
INSPECT HIGH±TENSION CORD
RESISTANCE
(See page IG±7)
Maximum resistance: 25 K
per cord
INSPECTION OF DRIVE BELT
INSPECT DRIVE BELT
HINT: A belt tensioner is used, so checking the belt tension
is not necessary.
(a) Visually check the drive belt for excessive wear, frayedcords etc.
If necessary, replace the drive belt.
HINT: Cracks on rib side of a drive belt are considered accept-
able. If the drive belt has chunks missing from the ribs, it
should be replaced.
(b) Check the belt tensioner operation.
w 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.
w Check the alignment of the belt tensioner pulley to
make sure the drive belt has not slipped off the
pulley.
If necessary, replace the belt tensioner.
w 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:
w When a new belt is installed, it should lie within area B.
If not, the drive is not correct.
w After installing a belt, check that it fits properly in the
ribbed grooves.
w 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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ENGINE MECHANICAL Engine Tune±UpEM±9
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INSPECTION AND ADJUSTMENT OF
VALVE CLEARANCE
HINT: Inspect and adjust the valve clearance when the en-
gine is cold.
1. DISCONNECT CABLE FROM NEGATIVE TERMINAL OF BATTERY
CAUTION: Turn the ignition switch to ºLOCKº. Discon-
nect the cable from the negative (±) terminal of the bat-
tery. Wait at least 20 seconds before procceding with
work.
2. DISCONNECT CONTROL CABLES FROM THROTTLE BODY
Disconnect the following cables:(1) Accelerator cable
(2) (A/T) Throttle control cable
(3) Cruise control actuator cable
3. REMOVE AIR CLEANER HOSE (a) Disconnect the following hoses:(1) PS air hose from No.
4 timing belt cover
(2) PCV hose from No. 2 cylinder head cover
(b) Loosen the two hose clamps and remove the air cleaner
hose.
4. REMOVE EGR PIPE (a) Loosen the union nut.
(b) Remove the two bolts, EGR pipe and gasket.
5. REMOVE THROTTLE BODY BRACKET Remove the four nuts and throttle body bracket.
EM±10
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ENGINE MECHANICAL Engine Tune±Up
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6. REMOVE THROTTLE BODY WITH INTAKE AIRCONNECTOR
(a) Disconnect the following hoses and connectors:(1) PCV hose
(2) Three vacuum hoses
(3) VSV (for EGR) connector
(4) Throttle position sensor connector
(5) IAC valve connector
(6) (w/ TRAC)
Sub±throttle position sensor connector
(7) (w/ TRAC) Sub±throttle actuator connector
(8) (USA spec. only)
EGR gas temperature sensor connector
(b) Remove the four bolts and two nuts holding the intake air connector to the intake chamber.
(c) Remove the VSV nut.
(d) Disc onnect the two water by±pass hoses from the
throttle body. Plug the hose ends.
(e) Remove the throttle body with the intake air connector and gasket.
7. REMOVE NO. 3 TIMING BELT COVER AND CYLINDER
HEAD REAR COVER
(a) Remove the oil filler cap.
(b) Using a 5 mm hexagon wrench, remove the ten bolts,No. 3 timing belt cover and cylinder head rear cover.
8. DISCONNECT HIGH±TENSION CORDS FROM SPARK PLUGS
(a) Remove the bolt holding the cord clamp from thecylinder head.
(b) Disconnect the two high±tension cord clamps from the No. 3 cylinder head cover.
(c) Disconnect the high±tension cords at the rubber boot. Do not pull on the cords.
NOTICE: Pulling on or bending the cords may damage
the conductor inside.
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ENGINE MECHANICAL Engine Tune±UpEM±11
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9. REMOVE NO. 3, NO. 1 AND NO. 2 CYLINDER HEADCOVERS
(a) Remove the 12 bolts and four nuts.
(b) Remove the cylinder head covers and gaskets.
10. SET NO. 1 CYLINDER TO TDC/COMPRESSION (a) Turn the crankshaft pulley and align its groove withtiming mark º0º of the No. 1 timing belt cover.
NOTICE: Always turn the crankshaft clockwise.
(b) Check that the timing marks of the camshaft timing pulleys are aligned with the timing marks of the No. 4
timing belt cover.
If not, turn the crankshaft one revolution (360 5).
11. INSPECT VALVE CLEARANCE (a) Uniformly tighten the bearing cap bolts in severalpasses.
Torque: 20 N Vm (200 kgf Vcm, 14 ft Vlbf)
(b) Check only those valves indicated in the illustration.
w Using a feeler gauge, measure the clearance
between the valve lifter and camshaft.
w Record the valve clearance measurements of
those that are out of specification. 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.)
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ENGINE MECHANICAL Engine Tune±Up
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(c) Turn the crankshaft 2/3 of a revolution (240
), check
only the valves indicated in the illustration.
Measure the valve clearance.
[See procedure in step (b)]
(d) Turn the crankshaft a further 2/3 of a revolution (240
),
check only the valves indicated in the illustration.
Measure the valve clearance.
[See procedure in step (b)]
12. ADJUST VALVE CLEARANCE (a) Remove the adjusting shim.w Turn the camshaft so that the cam lobe for the valve
to be adjusted faces up.
w Turn the valve lifter with a screwdriver so that the
notches would be per pendicular to the camshaft.
w Using SST (A), press down the valve lifter and
place SST (B) between the camshaft and valve
lifter. Remove SST (A).
SST 09248±55020 (09248±05011 (A), 09248±05021 (B))
HINT:
w Choose either method A or B in using SST on either side
of the cam lobe.
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ENGINE MECHANICAL Engine Tune±UpEM±13
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