cooling lexus LS400 1998 Audio System / LEXUS 1998 LS400 OWNER'S MANUAL (OM50498U)

GAUGES, METERS AND SERVICE REMINDER INDICATORS
35 Idling for a long period with the air conditioning on in
stopandgo traffic.
Towing a trailer.
NOTICE
Do not remove the thermostat in the engine cooling system as
this may cause the engine to overheat. The thermostat is
designed to control the flow of coolant to keep the
temperature of the engine within the specified operating
range.
Do not continue driving with an overheated engine. See ”If
your vehicle overheats” on page 196.
TACHOMETER
13L0031
The tachometer indicates engine speed in thousands of rpm
(revolutions per minute). Use it while driving to prevent engine
overrevving.
Driving with the engine running too fast causes excessive engine
wear and poor fuel economy. Remember, in most cases the slower
the engine speed, the greater the fuel economy.
NOTICE
Do not let the indicator needle get into the red zone. This may
cause severe engine damage.

AIR CONDITIONING AND AUDIO
126If quick heating or cooling is desired
Push the ”TEMP” or ”PASSENGER TEMP” button on either side
and hold it until ”MAX. HOT” or ”MAX. COLD” appears on the
display.
If manual fan speed control is desired
21L007-3
1
Fan speed at low 2
Fan speed at high
The fan speed can be set to your desired speed by pushing the
appropriate side of fan speed control button. The higher the fan
speed is, the more air is delivered. Pushing the ”OFF” button turns
off the fan.
To remove exterior windshield frost, use the high speed setting.If manual switching of air intake is desired
21L008-4
Each time you push the air intake control button, the mode changes
in order from the RECIRCULATED AIR mode to AUTOMATIC
mode to OUTSIDE AIR mode, then back to the RECIRCULATED
AIR mode. Each indicator light shows which mode is now selected.
1
RECIRCULATED mode If quick circulation of cooled air
is desired, select this mode.
2
AUTOMATIC mode When driving where the outside air is
dirty (i.e., when the vehicle running just in front of your vehicle
accelerates rapidly), the system changes automatically from
the OUTSIDE AIR mode to the RECIRCULATED mode.
3
OUTSIDE AIR mode The system will take fresh outside air
into the vehicle.

AIR CONDITIONING AND AUDIO
127 For normal use, it is best to keep the air intake control button set to
OUTSIDE AIR mode. If recirculated air is used during heating, the
windows will fog up more easily.
To change the sensitivity of the sensor switching between the
RECIRCULATED and OUTSIDE AIR in the AUTOMATIC
mode, push the air intake control button until you hear a beep.
The display changes as illustrated below.
21L044
Each time you push the ”TEMP” button, the sensitivity changes from
”+3” down to ”3”. If you do not operate any button for a few
seconds, the previous display returns.If manual onoff of the air conditioning is desired
Push the ”A/C” button to turn the air conditioning on and push it
again to turn the air conditioning off.
The air conditioning does not work if the outside temperature is
lowered down to around 0C (32F).
If the system is used for ventilation, heating in dry weather or
removing frost or exterior fog on the windshield, turn the air
conditioning off once it is no longer required. This will improve fuel
economy. The air conditioning can be used for yearround
automatic temperature control including cooling and dehumidifying
operation.
If the air conditioning compressor does not operate, the indicator of
the ”A/C” button will blink. If the indicator of the ”A/C” button
blinks even when the ”A/C” button is pushed again, have the
compressor checked by your nearest Lexus dealer.

STARTING AND DRIVING
156To ensure that the threeway catalytic converter and the
entire emission control system operate properly, your vehicle
must receive the periodic inspections required by the Lexus
Maintenance Schedule. For scheduled maintenance
information, refer to the separate ”Owner’s Manual
Supplement/ Maintenance Schedule”.
ENGINE EXHAUST CAUTION
CAUTION
Avoid inhaling the engine exhaust. It contains carbon
monoxide, which is a colorless and odorless gas. It can
cause unconsciousness or even death.
Make sure the exhaust system has no holes or loose
connections. The system should be checked from time to
time. If you hit something, or notice a change in the sound
of the exhaust, have the system checked immediately.
Do not run the engine in a garage or enclosed area except
for the time needed to drive the vehicle in or out. The
exhaust gases cannot escape, making this a particularly
dangerous situation.
Do not remain for a long time in a parked vehicle with the
engine running. If it is unavoidable, however, do so only in
an unconfined area and adjust the heating or cooling
system to force outside air into the vehicle.
Keep the trunk lid closed while driving. An open or
unsealed trunk lid may cause exhaust gases to be drawn
into the vehicle. If you must drive with the trunk lid open
to accommodate a large object, close the windows, open all
the dashboard vents and have the heating or cooling system
deliver fresh air into the vehicle by turning the fan to high
speed with the air intake control button in the OUTSIDE
AIR mode.
To allow proper operation of your vehicle’s ventilation
system, keep the inlet grilles in front of the windshield clear
of snow, leaves, or other obstructions.
If you smell exhaust fumes in the vehicle, drive with the
windows open and the trunk lid closed. Have the cause
immediately located and corrected.

IN CASE OF AN EMERGENCY
197 B: If no steam is coming from your engine:
Leave the engine running and turn off the air conditioning. Check
the following.
Is the cooling fan operating?
Is the coolant in the acceptable range?
Is the engine drive belt O.K.?
CAUTION
When the engine is running, keep hands and clothing away
from the moving fan and engine drive belt.
Do not attempt to remove the radiator cap when the engine
and radiator are hot. Serious injury could result from
scalding hot fluid and steam blown out under pressure.
If the cooling fan is not operating or the coolant is not in the
acceptable range, turn off the engine and call your Lexus dealer.
If both conditions are O.K., after the engine coolant temperature has
cooled to normal, continue driving your vehicle.
If the engine coolant temperature does not cool down, or your
vehicle overheats again, have it checked as soon as possible by your
Lexus dealer.
IF YOU HAVE A FLAT TIRE
1. Reduce your speed gradually, keeping a straight line. Move
cautiously off the road to a safe place well away from the traffic.
Avoid stopping on the center divider of a highway. Park on a level
spot with firm ground.
2. Stop the engine and turn on your emergency flashers.
3. Firmly set the parking brake and put the transmission in ”P”.
4. Have everyone get out of the vehicle on the side away from
traffic.
5. Read the following instructions thoroughly.
NOTICE
For vehicles equipped with the height control switch, be sure to
turn the ignition switch off before jacking. If this is not done, the
vehicle height adjustment function will operate, which may
cause body damage.
CAUTION
When jacking, be sure to observe the following to reduce the
possibility of personal injury:
Follow jacking instructions.
Do not start or run the engine while your vehicle is
supported by the jack.

INTRODUCTION
221
DOITYOURSELF SERVICE
PRECAUTIONS
If you perform maintenance yourself, be sure to follow the
correct procedure given in this Section.
You should be aware that improper or incomplete servicing may
result in operating problems.
Performing doityourself maintenance during the warranty period
may affect your warranty coverage. Read the separate Lexus
Warranty statement for details and suggestions.
This Section gives instructions only for those items that are
relatively easy for an owner to perform. As explained in Section 5,
there are still a number of items that must be performed by a qualified
technician with special tools.
For information on tools and parts for doityourself maintenance,
see ”Parts and tools”.
Utmost care should be taken when working on your vehicle to
prevent accidental injury. Here are a few precautions that you should
be especially careful to observe:
CAUTION
When the engine is running, keep hands, clothing, and tools
away from the moving fan and engine drive belt.
(Removing rings, watches, and ties is advisable.)
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 around
fuel or the battery. Their fumes are flammable.
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. Always use automotive jack stands or other
solid supports.
Be sure the ignition is off if you work near the electric
cooling fan or radiator grille. With the ignition on, the
electric cooling fan may automatically start to run if the air
conditioning is on and/or if the coolant temperature is high.
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

ENGINE
226 COOLING SYSTEM
Capacity
Coolant type
10.8 L (11.4 qt., 10.4 lmp.qt.)
Ethylene glycol coolant (Do not use alcohol type.)
FUEL
Fuel type
Octane rating
Only UNLEADED
91 (Research octane number 96) or higher
IGNITION SYSTEM
Spark plug Make DENSO
NGK
Gap
SK20R11
IFR6A11
1.1 mm (0.043 in.)
ELECTRICAL SYSTEM
Battery Maintenance type battery
Specific gravity reading at 20C (68F):
Charging rates Quick charge
Slow charge
Nonmaintenance battery
Open voltage at 20C (68F):
Charging rates
1.260 Fully charged
1.160 Half charged
1.060 Discharged
15A max.
5A max.
12.7V Fully charged
12.3V Half charged
11.9V Discharged
[Voltage that is checked 20 minutes after the key is removed with
all the lights turned off]
5A max.

ENGINE
229
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.The 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 highspeed 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

ENGINE
233
CHECKING THE ENGINE
COOLANT LEVEL
62L007-2
1
Reservoir cap 2
Upper line 3
Lower line
Park the vehicle at a level spot and look at the seethrough
coolant reservoir when the engine is cool. The coolant level is
satisfactory if it is between the upper and lower lines on the tank.
If the level is low, add ethyleneglycol type coolant.
The coolant level in the reservoir will vary with engine coolant
temperature. However, if the level is on or below the lower line, add
coolant to bring the level up to the upper line.
Use only ethyleneglycol type coolant. It will prevent freezing and
corrosion. Neither supplemental inhibitors nor additives are needed
nor recommended. (For information on ethyleneglycol coolant,
see also ”Engine coolant selection” described below.)If the coolant level drops within a short time after replenishing, there
may be a leak in the system. Visually check the radiator, hoses,
reservoir cap, drain cock and water pump.
If you can find no leak, have your Lexus dealer test the cap pressure
and check for leaks in the cooling system.
CAUTION
To prevent burning yourself, do not remove the reservoir cap
when the engine is hot.
Engine coolant selection
Your coolant must contain ethyleneglycol antifreeze. In addition
to preventing freezing and subsequent damage to the engine, this
will also prevent corrosion. Further supplemental inhibitors or
additives are neither needed nor recommended.
Read the antifreeze container for information on freeze protection.
Follow the manufacturer’s directions for how much to mix with
water. The total capacity of the cooling system is given on page 226.
We recommend 50% solution be used for your Lexus, or a sufficient
quantity to provide protection to about 35C (31F).
NOTICE
Do not use alcohol type antifreeze or plain water alone.

CHASSIS
247
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 removed 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.
SUSPENSION AND CHASSIS
CAUTION
Do not modify the suspension/chassis with lift kits, spacers,
springs, etc. It can cause dangerous handling characteristics,
resulting in loss of control.