1991 LEXUS SC400 coolant

The 1 UZ±FE engine has 8±cylinders in a V±arrangement at a bank an\
gle of 905. From the front of the RH
bank cylinders are numbered 2 ± 4 ± 6 ± 8, and from the front of t\
he LH bank cylinders are 1 ± 3 ± 5 ± 7.
The crankshaft is supported by 5 bearings inside the crankcase. These beari\
ngs are made of a copper and
lead alloy.
The crankshaft is integrated with 8 weights for balance. Oil holes are plac\
ed in the center of the crankshaft
to supply oil to the connecting rods, bearing, pistons and other component\
s.
The ignition order is 1 ± 8 ± 4 ± 3 ± 6 ± 5 ± 7 ± 2. T\
he cylinder head is made of alminum alloy, with a cross
flow type intake and exhaust layout and with pent±roof type combustion chambers. The spark plugs are
located in the center of the combustion chambers.
At the front and rear of the intake manifold, a water passage has been p\
rovided which connects the RH
and LH cylinder heads.
Exhaust and intake valves are equipped with irregular pitch springs made\
of special valve spring carbon
steel which are capable of functioning at all engine speeds.
The RH and LH intake camshaft are driven by a timing belt, and a gear on\
the intake camshaft engages
with a gear on the exhaust camshaft to drive it. The cam journal is supp\
orted at 5 (intake) or 4 (exhaust)
places between the valve lifters of each cylinder and on the front end o\
f the cylinder head. Lubrication of
the cam journals and gears is accomplished by oil being supplied through th\
e oiler port in the center of the
camshaft.
Adjustment of the valve clearance is done by means of an outer shim type\
system, in which valve adjusting
shims are located above the valve lifters. This permits replacement of the sh\
ims without removal of the
camshafts.
Pistons are made of high temperature±resistant aluminum alloy, and a depression is built into the piston
head to prevent interference with the valves.
Piston pins are the full±floating type, with the pins fastened to neither the piston boss nor the connecting
rods. Instead, snap rings are fitted on both ends of the pins, preventing the\
pins from falling out.
The No.1 compression ring is made of steel and the No.2 compression ring\
is made of cast iron. The oil
ring is made of a combination of steel and stainless steel. The outer diamet\
er of each piston ring is slightly
larger than the diameter of the piston and the flexibility of the rings allows them to hug the cylinder walls
when they are mounted on the piston. Compression rings No.1 and No.2 work to\
prevent gas leakage from
the cylinder and the oil ring works to scrape oil off the cylinder walls to prevent it from entering the combus-
tion chambers.
The cylinder block is made of aluminum alloy with a bank of 90 5. Cast iron cylinders are installed inside
the cylinder block. It has 8 cylinders which are approximately twice the le\
ngth of the piston stroke. The top
of each cylinder is closed off by the cylinder head and the lower end of the cylinders becomes the crank-
case, in which the crankshaft is installed. In addition, the cylinder block c\
ontains a water jacket, through
which coolant is pumped to cool the cylinders.
The No.1 and No.2 oil pans are bolted onto the bottom of the cylinder bl\
ock. The No.1 oil pan is made of
aluminum alloy. The No.2 oil pan is an oil reservoir made of pressed steel sheet. An o\
il level sensor is
installed in the No.1 oil pan (If oil level drops below a set level, a warning light\
s up.). And oil pan baffle plate
keeps sufficient oil in the bottom of the No.2 oil pan even when the vehicle is t\
ilted. This dividing plate also
prevents the oil from marking waves when the vehicle is stopped suddenly\
and the oil shifts away from the
oil pump suction pipe.
Plastic region tighten bolts are used for the cylinder head, main bearin\
g cap and connecting rod.
EG±4
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1UZ±FE ENGINE ENGINE MECHANICAL
WhereEverybodyKnowsYourName

\
 \

Spring tester Valve spring
\
 
\

\
Steel square 

Valve spring
\
 
\

\

Thermometer 


\
 \
Torque wrench 
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Valve seat cutter 


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Vernier calipers 

EG0B1±0A
COOLANT
 Item Capacity Classification
 Engine coolant (w/ Heater) 10.8 liters (11.4 US qts, 9.5 lmp. qts) Ethylene±glycol base
EG0B1±10
LUBRICANT
 Item Capacity Classification
 Engine oil  API grade SG or SH, Energy±Conserving II
 Dry fill 6.0 liters (6.3 US qts, 5.3 lmp. qts) or ILSAC multigrade and recommended
 Drain and refill  viscosity oil with SAE 5W±30
 w/ Oil filter change 4.8 liters (5.1 US qts, 4.2 lmp. qts) being the preferred engine oil
 w/o Oil filter change 4.5 liters (4.8 US qts, 4.0 lmp. qts) 
EG0B1±0J
SSM (SERVICE SPECIAL MATERIALS)
 08826±00080 Seal packing or equivalent Camshaft bearing cap
   Cylinder head semi±circular plug
   Cylinder head cover
   Rear oil sear retainer
 08826±00080 Seal packing or equivalent Oil pump
   
   
   
 08826±00100 Seal Packing 1282B, Water inlet housing
  THREE BOND 1282B or equivalent Water seal plate
   Water pump
   
 08833±00070 Adhesive 1311, Drive plate bolt
  THREE BOND 1311 or equivalent 
   
   
 08833±00080 Adhesive 1344 No.1 idler pulley bolt
  THREE BOND 1344. 
  LOCTITE 242 or equivalent 
   
EG±8±
1UZ±FE ENGINE ENGINE MECHANICAL
WhereEverybodyKnowsYourName

TUNE±UP
EG10Z±05
ENGINE COOLANT INSPECTION
1. CHECK ENGINE COOLANT LEVEL AT RESERVOIR TANK
The coolant level should be above the ªCOLD LEVELº at nor-
mal temperature (20 5C (68 5F)).
If low, check for leaks and add coolant up to the ªCOLD LEV-
ELº
2. CHECK ENGINE COOLANT QUALITY
(a) Remove the radiator cap from the reservoir tank.
CAUTION: To avoid the danger of being burned, do not remove
it while the engine and radiator are still hot as fluid and steam
can be blown out under pressure
(b) There should not be any excessive deposits of rust or scale around the radiator cap or reservoir tank filler hole, and the
coolant should be free from oil.
If excessively dirty, clean the coolant passages and replace
the coolant.
Capacity (w/ Heater):
10.8 liters (11.4 US qts, 9.5 lmp. qts)
HINT:
wUse a good brand of ethylene±glycol base coolant and
mix it according to the manufacturer's directions.
w Using coolant which includes more than 50%
ethylene±glycol(but not more than 70%) is
recommended.
NOTICE:
w Do not use a alcohol type coolant.
w The coolant should be mixed with demineralized water or
distilled water.
(c) Reinstall the radiator cap.
±
1UZ±FE ENGINE ENGINE MECHANICALEG±9
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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 ªLOCKº 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
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40. RECONNECT NEGATIVE TERMINAL CABLE TOBATTERY
41. REFILL WITH ENGINE COOLANT
42. START ENGINE AND CHECK FOR LEAKS
EG21T±02
IGNITION TIMING INSPECTION
1. 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.
2. WARM UP ENGINE Allow the engine to warm up to normal operating tempera-
ture.
3. CONNECT TACHOMETER AND TIMING LIGHT TO ENGINE
Connect the tester probe of a tachometer to terminal IG
of
the DLC1.
HINT: Set the tachometer to the 4±cylinder range.
NOTICE:
w Never allow the tachometer terminal to touch ground as
it could result in damage to the igniter and/or ignition
coil.
w As some tachometers are not compatible with this
ignition system, we recommend that you confirm the
compatibility of your unit before use.
4. INSPECT IGNITION TIMING
(a) Using SST, connect terminals TE1 and E1 of the DLC 1.
SST 09843±18020
EG±32
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1UZ±FE ENGINE ENGINE MECHANICAL
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EG21P±02
TIMING BELT REMOVAL
(See Components for Removal and Installation)
1. REMOVE BATTERY CAUTION: Work must be started after 90 seconds from
the time the ignition switch is turned to the ªLOCKº posi-
tion and the negative (±) terminal cable is disconnected
from the battery.
2. REMOVE ENGINE UNDER COVER
3. DRAIN ENGINE COOLANT
4. REMOVE DRIVE BELT
Loosen the drive belt tension by turning the drive belt tension-
er counterclockwise, and remove the drive belt.
HINT: The pulley bolt for the drive belt tensioner has a left±
hand thread.
5. REMOVE RADIATOR RESERVOIR TANK
(a) Disconnect the coolant level sensor connector.
(b) Disconnect the following hoses: (1) Reservoir hose from water inlet housing
(2) Reservoir hose from radiator
(c) Remove the 2 bolts and reservoir tank bracket.
(d) Remove the bolt holding the reservoir tank to the radiator.
(e) Disconnect the reservoir tank from the reservoir tank bracket,
and remove the reservoir tank.
6. REMOVE RADIATOR ASSEMBLY
(a) Disconnect the ECT sensor connector (for cooling fan).
(b) Disconnect the ECT sensor wire clamp from the radiator fan shroud.
EG±46
±
1UZ±FE ENGINE ENGINE MECHANICAL
WhereEverybodyKnowsYourName

39. INSTALL RADIATOR RESERVOIR TANK
(a) Install the reservoir tank to the reservoir tank bracket.
(b) Install the reservoir tank with the bracket and 3 bolts.
Torque: 4.9 NVm (50 kgf Vcm, 43 in. Vlbf)
(c) Connect the following hoses:
(1) Reservoir hose to water inlet housing
(2) Reservoir hose to radiator
(d) Connect the coolant level sensor connector.
40. INSTALL DRIVE BELT Install the drive belt by turning the drive belt tensioner coun-
terclockwise.
HINT: The pulley bolt for the dive belt tensioner has a left
hand thread.
41. INSTALL BATTERY
42. FILL WITH ENGINE COOLANT
43. START ENGINE AND CHECK FOR LEAKS
44. CHECK TRANSMISSION FLUID LEVEL
45. INSTALL ENGINE UNDER COVER
EG±72
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1UZ±FE ENGINE ENGINE MECHANICAL
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45. INSTALL LH CAMSHAFT TIMING PULLEY
(a) Align the camshaft knock pin with the knock pin groove of the
timing pulley, and slide on the timing pulley.
(b) Slide the timing pulley on the camshaft, facing the ªLº mark forward.
(c) Using SST, install the pulley bolt. SST 09278±54012
Torque: 108 N Vm (1,100 kgf Vcm, 80 ft Vlbf)
46. C O N N E C T T I M I N G B E LT TO C A M S H A F T T I M I N G
PULLEYS
(See steps 10 to 40 on pages EG±61 to 72)
47. CONNECT NEGATIVE TERMINAL CABLE TO BATTERY
48. FILL WITH ENGINE COOLANT
49. START ENGINE AND CHECK FOR LEAKS
50. CHECK TRANSMISSION FLUID LEVEL
51. PERFORM ENGINE ADJUSTMENT (See Tune±Up on pages EG±9 to 34)
52. PERFORM ROAD TEST Check for abnormal noise, shock, slipage, correct shift points
and smooth operation.
53. INSTALL ENGINE UNDER COVER
EG±136
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1UZ±FE ENGINE ENGINE MECHANICAL
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