air LEXUS SC300 1999 Manual Online

MAINTENANCE
315
DOES YOUR VEHICLE NEEDREPAIRING?
Be on the alert for changes in performance and sounds, and
visual tip±offs that indicate service is needed. Some
important clues are:

Engine missing, stumbling, or pinging

Appreciable loss of power

Strange engine noises

A fluid leak under the vehicle (However, water dripping
from the air conditioning after use is normal.)

Change in exhaust sound (This may indicate a dangerous
carbon monoxide leak. Drive with the windows open and
have the exhaust system checked immediately.)

Flat±looking tires, excessive tire squeal when cornering,
uneven tire wear

Vehicle pulls to one side when driving straight on a level
road

Strange noises related to suspension movement

Loss of brake effectiveness, spongy feeling brake pedal,
pedal almost touches floors, vehicle pulls to one side when
braking

Engine coolant temperature continually higher than
normal
If you notice any of these clues, take your vehicle to your
Lexus dealer as soon as possible. It probably needs
adjustment or repair.

INTRODUCTION
325

Right after driving, the engine compartment ± the
engine, radiator, exhaust manifold and power
steering fluid reservoir, etc. ± will be hot. So be
careful not to touch them. Oil and other fluids may
also be hot.

Do not smoke, cause sparks or allow open flames
near fuel or the battery. Their fumes are fl ammable.

Be extremely cautious when working on the battery.
It contains poisonous and corrosive sulfuric acid.

Do not get under your vehicle with just the body jack
supporting it. Al ways use automotive jack stands or
other solid supports.

Use eye protection whenever you work on or under
your vehicle where you may be exposed to flying or
falling material, fluid spray, etc.
NOTICE

Remember that battery and ignition cables carry high
currents or voltages. Be careful of accidentally
causing a short circuit.

Before closing the engine hood, check to see that you
have not forgotten any tools, rags, etc.

Do not drive with the air cleaner removed, or excessive
engine wear could result. Also backfiring could cause
a fire in the engine compartment.

Do not overfill automatic transmission fluid, or the
transmission could be damaged.

Be careful not to scratch the glass surface with the
wiper frame.
PARTS AND TOOLS
Here is a list of parts and tools you will need to perform
do±it±yourself maintenance. Remember all Lexus parts are
designed in metric sizes, so your tools must be metric.
Checking the engine oil level
Parts (if level is low):

Use API grade SJ, ºEnergy±Conservingº multigrade
engine oil or ILSAC multigrade engine oil. For
recommended oil viscosity, see page 346.
Tools:

ENGINE
339
Gasolines quality
In a very few cases, you may experience driveability
problems caused by the particular gasoline that you are using.
If you continue to have unacceptable driveability, try
changing gasoline brands. If that does not rectify your
problem, then consult your Lexus dealer.
NOTICE

Do not use gasohol other than stated above. It will
cause fuel system damage or vehicle performance
problems.

If drivability problems are encountered (poor hot
starting, vaporizing, engine knock, etc.), discontinue
its use.

Take care not to spill gasohol during refueling.
Gasohol may cause paint damage.
Fuel tank capacity
78 L (20.6 gal., 17.2 lmp.gal.)
FACTS ABOUT ENGINE OIL
CONSUMPTION
Functions of engine oil
Engine oil has the primary function of lubricating and cooling
the inside of the engine, and plays a major role in maintaining
the engine in proper working order.
Engine oil consumption
It is normal that an engine should consume some engine
oil during normal engine operation. The causes of oil
consumption in a normal engine are as follows.

Oil is used to lubricate pistons, piston rings and cylinders.
A thin film of oil is left on the cylinder wall when a piston
moves downwards in the cylinder. High negative pressure
generated when the vehicle is decelerating sucks some of
this oil into the combustion chamber. This oil as well as
some part of the oil film left on the cylinder wall is burned
by the high temperature combustion gases during the
combustion process.

Oil is also used to lubricate the stems of the intake valves.
Some of this oil is sucked into the combustion chamber
together with the intake air and is burned along with the
fuel. High temperature exhaust gases also burn the oil
used to lubricate the exhaust valve stems.

ENGINE
340The amount of engine oil consumed depends on the
viscosity of the oil, the quality of the oil and the way the
vehicle is driven.
More oil is consumed by high±speed driving and frequent
acceleration and deceleration.
A new engine consumes more oil, since its pistons, piston
rings and cylinder walls have not become conditioned.
When judging the amount of oil consumption, keep in
mind that the oil may have become diluted, making it
difficult to judge the true level accurately.
For example, if a vehicle is used for repeated short trips and
consumes a normal amount of oil, the dipstick may not show
any drop in the oil level at all, even after 1000 km (600 miles)
or more. This is because the oil is gradually becoming diluted
with fuel or moisture, making it appear that the oil level has
not changed.
The diluting ingredients evaporate out when the vehicle is
then driven at high speeds, as on an expressway, making it
appear that oil is excessively consumed after driving at high
speeds.
Importance of engine oil level check
One of the most important points in proper vehicle
maintenance is to keep the engine oil at the optimum level so
that
oil function will not be impaired. Therefore, it is essential
that the oil level be checked regularly. Lexus recommends
that the oil level be checked every time you refuel the vehicle.
NOTICE
Failure to check the oil level regularly could lead to
serious engine trouble due to insufficient oil.
For detailed information on oil level check, see ºChecking the
engine oil levelº on page 342.

CHASSIS
360It is normal for the brake fluid level to go down slightly as the
brake pads wear. So be sure to keep the reservoir filled.
If the reservoir needs frequent refilling, it may indicate a
serious mechanical problem.
If the level is low, add FMVSS No.116 DOT 3 or SAE
J1703 brake fluid to the brake reservoir.
Remove and replace the reservoir cover by hand. Add brake
fluid up to the ºMAXº line.
Use only newly opened brake fluid. Once opened, brake fluid
absorbs moisture from the air, and excess moisture can cause
a dangerous loss of braking efficiency.
CAUTION
Take care when filling the reservoir because brake fluid can
harm your hands or eyes and damage painted surfaces. If
fluid gets in your hands or eyes, flush them with clean water.
NOTICE

If you spill some of the fluid, be sure to wipe it off to
prevent it from damaging the parts or paintwork.
 For vehicles with traction control system only:Idle
the engine while pouring brake fluid into the reservoir.

CHASSIS
364The recommended cold tire pressures, tire size and the
vehicle capacity weight are given on the label.
You should check the tire pressures every two weeks, or at
least
once a month. And don't forget the spare! The pressure
for the spare tire should be same with that for the standard tire.
(See page 356 or 358.) Incorrect tire pressure can reduce tire
life and make your vehicle less safe to drive.
Low tire pressure results in excessive wear, poor handling,
reduced fuel economy, and the possibility of blowouts from
overheated tires. Also, low tire pressure can cause poor
sealing of the tire bead. If the tire pressure is excessively low,
there is the possibility of wheel deformation and/or tire
separation. So keep your tire pressures at the proper level. If
a tire needs frequent refilling, have it checked by your Lexus
dealer. High tire pressure produces a harsh ride, handling problems,
excessive wear at the center of the tire tread, and a greater
possibility of tire damage from road hazards.
The following instructions for checking tire pressure should
be observed:

The pressure should be checked only when the tires are
cold. If your vehicle has been parked for at least 3 hours
and has not been driven for more than 1.5 km or 1 mile
since, you will get an accurate cold tire pressure reading.
 Always use a tire pr essure gauge. The appearance of the
tire can be misleading. Besides, tire pressures that are even
just a few pounds off can degrade handling and ride.
 Do not bleed or reduce tire pressure after driving. It is
normal for the tire pressure to be higher after driving.
 Never exceed the vehicle capacity weight. The
passengers and luggage weight should be located so that
the vehicle is balanced.
 Be sure to reinstall the tire valve caps. Without the valve
caps, dirt or moisture could get into the valve core and
cause air leakage. If the caps have been lost, have new
ones put on as soon as possible.

CHASSIS
366
Replace the tires when the tread wear indicators show.
The location of the tread wear indicators is shown by the
ºTWIº or º
Dº marks molded on the sidewall of each tire.
The tires on your Lexus have built±in tread wear indicators to
help you know when the tires need replacement. When the
tread depth wears to 1.6 mm (0.06 in.) or less, the indicators
will appear. If you can see the indicators in two or more
adjacent grooves, the tire should be replaced.
The effectiveness of snow tires is lost if the tread wears
down below 4 mm (0.16 in.).
If you have tire damage such as cuts, splits, cracks deep
enough to expose the fabric, or bulges indicating internal
damage, the tire should be replaced. If a tire often goes flat or cannot be properly repaired due to
the size or location of a cut or other damage, it should be
replaced. If you are not sure, consult with your Lexus dealer.
If an air loss occurs while driving, do not continue driving
with a deflated tire. Driving even a short distance can damage
a tire beyond repair.
Any tires which are over 6 years old must be checked by
a qualified technician even if damage is not obvious.
Tires deteriorate with age even if they have never or seldom
been used.
This also applies to the spare tire and tires stored for future
use.

CHASSIS
372
REPLACING WHEELS
When to replace your wheels
If you have wheel damage such as bending, cracks or
heavy corrosion, the wheel should be replaced.
If you fail to replace damaged wheels, a tire may slip off a
wheel or they may cause loss of handling control.
Replacement with used wheels is not recommended as they
may have been subjected to rough treatment or high mileage
and could fail without warning. Also, bent wheels which have
been straightened may have hidden structural damage and
therefore should not be used. Never use an inner tube in a
leaking wheel which is designed for a tubeless tire.
Wheel selection
When replacing wheels, care should be taken to ensure
that they are equivalent to those rem oved in load capacity,
diameter, rim width, and offset.
Correct replacement wheels are available at your Lexus
dealer.
A wheel of a different size or type may adversely affect
handling, wheel and bearing life, brake cooling,
speedometer/odometer calibration, stopping ability,
headlight aim, bumper height, vehicle ground clearance, and
tire or snow chain clearance to the body and chassis.
ALUMINUM WHEEL PRECAUTIONS
After driving your vehicle the first 1600 km (1000 miles),
check that the wheel nuts are tight.
 If you have rotated, repaired, or changed your tires, check
that the wheel nuts are still tight after driving 1600 km
(1000 miles).
 When using tire chains, be careful not to damage the
aluminum wheels.
 Use only the Lexus wheel nuts and wrench designed for
your aluminum wheels.
 When balancing your wheels, use only Lexus balance
weights or equivalent and a plastic or rubber hammer.
 As with any wheel, periodically check your aluminum
wheels for damage. If damaged, replace immediately.

Engine compartment
ELECTRICAL COMPONENTS
377
No.FUSEAMPERECIRCUIT
1ENGINE7.5Charging system
2HTR10Air conditioning system, rear
window defogger
3WIPER20Windshield wipers and washer
4ST7.5
Starting system, cruise control
system, multiport fuel injection
system/sequential multiport fuel
injection system, instrument panel
lights
5IGN7.5
Discharge warning light, multiport
fuel injection system/sequential
multiport fuel injection system,
SRS airbag system
6PANEL7.5Instrument panel lights, glovebox
light
7MIR±HTR10Outside rear view mirror defogger
8TURN7.5Turn signal lights
9STOP15Stop lights, cruise control system
cancel device
10CIG15
Cigarette lighter, theft deterrent
system, shift lock system, SRS
airbag system, instrument panel
lights

ELECTRICAL COMPONENTS
378
No.FUSEAMPERECIRCUIT
11RADIONO.27.5Radio, cassette tape player,
compact disc player, power
antenna, power rear view mirrors
12TAIL7.5Tail lights, parking lights, side
marker lights, license plate lights
13ECU±IG15
Cruise control system, power
steering control system, shift lock
system, anti±lock brake system,
SRS airbag system, power door
lock system, preset steering system,
traction control system,
electronically controlled
hydraulic±driven cooling system,
passenger 's seat control system
14GAUGE10
Gauges and meters, service
reminder indicators and warning
buzzers (except discharge and open
door warning lights), back±up
lights, electronically controlled
automatic transmission system,
automatic transmission overdrive
system, headlight
15ECU±B15SRS airbag system, power rear
view mirrors
16OBD7.5On±board diagnosis system
17FOG15Fog lights
18SEAT±HT R15Seat heater