1991 LEXUS SC400 oil temperature

2. INSPECT OIL PRESSUREHINT: Before inspecting the oil pressure, first check that the
A/C is off.
(a) Using SST, connect terminals OP1 and E1 of the check(ºDIAGNOSISº) connector.
SST 09843±18020
HINT: When terminals OP1 and E1 are connected, the circuit
of the water temp. sensor is grounded, fixing the fan speed
at approx. 1,100 rpm. (Fail±safe operation occurs.)
(b) Bleed the hydraulic cooling system
(See page CO±24)
(c) Keep the engine speed at 2,000 rpm until the fluid temperature reaches the specified temperature.
Fluid temp.: 70±90 5C (158±195 5F)
(d) Check the fluid level is correct.
(e) Measure the oil pressure at idling.
Oil pressure: 1,177±2,452 kPa
(12±25 kgf/cm, 171±356 psi)
(f) Remove the SST from the check connector.
SST 09843±18020
(g) Check that the oil pressure decreases.
3. REMOVE PRESSURE GAUGE, AND CONNECT PRESSURE HOSE
Torque: 64 N Vm (650 kgf Vcm, 47 ft Vlbf)
±
COOLIING SYSTEM Electronically Controlled Hydraulic
Cooling Fan (On±Vehicle Inspection)CO±25
WhereEverybodyKnowsYourName

6. DISCONNECT COOLING FAN INLET PIPE FROM FANSHROULD
Remove the two bolts, brackets and bushings, and discon-
nect the inlet pipe.
7. DISCONNECT COOLING FAN RESERVOIR TANK FROM FAN SHROULD
(a) Disconnect the suction hose from the clamp on the fanshrould.
(b) Remove the four bolts, and disconnect the reservoir tank.
8. REMOVE RADIATOR FAN SHROULD (a) Disconnect the wire clamp (for temperature sensor)from the radiator fan shrould.
(b) Remove the four bolts, and disconnect the fan shrould from the radiator.
(c) Slightly lift the fan shrould, and disconnect the two oil cooler hoses (for cooling fan) from the hose clamp on
the fan shrould.
(d) Remove the fan shrould.
±
COOLIING SYSTEM Electronically Controlled Hydraulic Cooling Fan
(Hydraulic Motor)CO±49
WhereEverybodyKnowsYourName

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
±
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
WhereEverybodyKnowsYourName

EG115±06
IDLE SPEED INSPECTION
1. INITIAL CONDITIONS
(a) Engine at normal operating temperature
(b) Air cleaner installed
(c) All pipes and hoses of air induction system connected
(d) All accessories switched OFF
(e) All vacuum lines properly connectedHINT: All vacuum hoses for EGR system, etc. should be prop-
erly connected.
(f) MFI system wiring connectors fully plugged
(g) Ignition timing set correctly
(h) Transmission in neutral position
2. CONNECT TACHOMETER 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.
3. INSPECT IDLE SPEED
(a) Race the engine speed at 2,500 rpm for approx. 90 seconds.
(b) Check the idle speed.
Idle speed:
700 + 50 rpm
If the idle speed is not as specified, check the IAC valve.
4. DISCONNECT TACHOMETER
EG±34
±
1UZ±FE ENGINE ENGINE MECHANICAL
WhereEverybodyKnowsYourName

C. If necessary, replace connecting rod bushing
(a) Using SST and a press, press out the bushing.SST 09222±30010
(b) Align the oil holes of a new bushing and the connecting rod.
(c) Using SST and a press, press out the bushing SST 09222±30010
(d) Using a pin hole grinder, hone the bushing to obtain the standard specified clearance (see step B above) between
the bushing and piston pin.
(e) Check the piston pin fit at normal room temperature. Coat the piston pin with engine oil, and push it into the con-
necting rod with your thumb.
D. Inspect connecting rod bolts Using a vernier caliper, measure the tension portion of of the
connecting rod bolt.
Standard diameter:
7.200 ± 7.300 mm (0.2835 ± 0.2874 in.)
Maximum diameter: 7.00 mm (0.2756 in.)
HINT: If the tension portion diameter is less than minimum,
replace the connecting rod bolt.
±
1UZ±FE ENGINE ENGINE MECHANICALEG±173
WhereEverybodyKnowsYourName

12. REMOVE RADIATOR RESERVOIR TANK(a) Disconnect the coolant level sensor connector.
(b) Disconnect the following hoses:(1) Reservoir hose to water inlet housing
(2) Reservoir hose to radiator
(c) Remove the two bolts and reservoir tank bracket.
(d) Disconnect the reservoir tank from the reservoir tank bracket, and remove the reservoir tank.
13. REMOVE RADIATOR (a) Disconnect the water temperature sensor connector.
(b) Disc onnect the wire clamp (for water temperature
sensor) from the radiator fan shrould.
(c) Disconnect the following hoses: (1) Two oil cooler hoses (for cooling fan) from pipes
(2) Two radiator hoses
EM±120
±
ENGINE MECHANICAL Cylinder Block
WhereEverybodyKnowsYourName

(b) Align the oil holes of the connecting rod and a newbushing.
(c) Using SST and a press, press in the bushing.
SST 09222±30010
(d) Using a pin hole grinder, hole the bushing to obtain the standard specified clearance (see step B above)
between the bushing and piston pin.
(e) Check the piston pin fit at normal room temperature.
Coat the piston pin with engine oil, and push it into the con-
necting rod with your thumb.
D. Inspect connecting rod bolts Using a vernier caliper, measure the tension portion diameter
of the bolt.
Standard diameter: 7.200±7.300 mm
(0.2835±0.2874 in.)
Minimum diameter: 7.00 mm (0.2756 in.)
If the outside diameter is less than minimum, replace the bolt.
EM±150
±
ENGINE MECHANICAL Cylinder Block
WhereEverybodyKnowsYourName