1998 Lexus LS400 engine overheat

DRIVING TIPS
188Because of the added load of the trailer, your vehicle’s engine
may overheat on hot days (at temperatures over 30C [85F])
when going up a long or steep grade with a trailer. If the engine
coolant temperature gauge indicates overheating, immediately
turn off the air conditioning (if in use), pull your vehicle off the
road and stop in a safe spot. See ”If your vehicle overheats” on
page 196 of this manual.
Always place wheel blocks under both the vehicle and trailer
wheels when parking. Apply the parking brake firmly. Put the
transmission in ”P”. Avoid parking on a slope with a trailer, but
if it cannot be avoided, do so only after performing the following:
1. Apply the brakes and keep them applied.
2. Have someone place wheel blocks under both the vehicle and
trailer wheels.
3. When the wheel blocks are in place, release your brakes slowly
until the blocks absorb the load.
4. Apply the parking brake firmly.
5. Shift into ”P” and turn off the engine.When restarting out after parking on a slope:
1. With the transmission in ”P” position, start the engine. Be sure
to keep the brake pedal depressed.
2. Shift into the ”3”, ”2”, ”L” or ”R” position.
3. Release the parking brake and brake pedal and slowly pull or back
away from the wheel blocks. Stop and apply your brakes.
4. Have someone retrieve the blocks.
CAUTION
Do not exceed 72 km/h (45 mph) or the posted towing speed
limit, whichever is lower. Because instability (swaying) of
a towing vehicletrailer combination usually increases as
the speed increases, exceeding 72 km/h (45 mph) may cause
loss of control.
Slow down and downshift before descending steep or long
downhill grades. Do not make sudden downshifts.
Avoid holding the brake pedal down too long or too
frequently. This could cause the brakes to overheat and
result in reduced braking efficiency.

DRIVING TIPS
189
HOW TO SAVE FUEL AND MAKE
YOUR VEHICLE LAST LONGER
Getting more kilometer/mileage from a liter/gallon of fuel is easy
just take it easy. It will help make your vehicle last longer, too. Here
are some specific tips on how to save money on both fuel and repairs:
Keep your tires inflated at the correct pressure. Check the
pressure every two weeks, or at least once a month.
Underinflation causes tire wear and wastes fuel.
Do not carry unneeded weight in your vehicle. Excess weight
puts a heavier load on the engine, causing greater fuel
consumption.
Avoid lengthy warmup idling. Once the engine is running
smoothly, begin driving but gently. Remember, however, that
on cold winter days this may take a little longer.
Accelerate slowly and smoothly. Avoid jackrabbit starts.
Avoid long engine idling. If you have a long wait and you are
not in traffic, it is better to turn off the engine and start again later.
Avoid engine overrevving. Use a gear position suitable for the
road on which you are traveling.
Avoid continuous speeding up and slowing down.
Stopandgo driving wastes fuel.Avoid unnecessary stopping and braking. Maintain a steady
pace. Try to time the traffic signals so you only need to stop as
little as possible or take advantage of through streets to avoid
traffic lights. Keep a proper distance from other vehicles to avoid
sudden braking. This will also reduce wear on your brakes.
Avoid heavy traffic or traffic jams whenever possible.
Do not rest your foot on the brake pedal. This causes needless
wear, overheating and poor fuel economy.
Maintain a moderate speed on highways. The faster you drive,
the greater the fuel consumption. By reducing your speed, you
will cut down on fuel consumption.
Keep the front wheels in proper alignment. Avoid hitting the
curb and slow down on rough roads. Improper alignment not only
causes faster tire wear but also puts an extra load on the engine,
which, in turn, wastes fuel.
Keep the bottom of your vehicle free from mud, etc. This not
only lessens weight but also helps prevent corrosion.
Keep your vehicle tunedup and in top shape. A dirty air
cleaner, improper valve clearance, dirty plugs, dirty oil and
grease, brakes not adjusted, etc. all lower engine performance and
contribute to poor fuel economy. For longer life of all parts and
lower operating costs, keep all maintenance work on schedule,
and if you often drive under severe conditions, see that your
vehicle receives more frequent maintenance. (For scheduled
maintenance information, please refer to the separate ”Owner’s
Manual Supplement/Maintenance Schedule”.)
CAUTION

SECTION 4
192
IN CASE OF AN EMERGENCY
If your engine stalls while driving 193. . . . . . . . . . . . . . . . . . . . . . . . . . . .
If your vehicle will not start 193. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If your vehicle overheats 196. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If you have a flat tire 197. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If your vehicle needs to be towed 205. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If you cannot shift automatic transmission
selector lever 209. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
If you lose your keys or lock yourself out 210. . . . . . . . . . . . . . . . . . . . . .

IN CASE OF AN EMERGENCY
193
IF YOUR ENGINE STALLS WHILE
DRIVING
If your engine stalls while driving . . . .
1. Reduce your speed gradually, keeping a straight line. Move
cautiously off the road to a safe place.
2. Turn on your emergency flashers.
3. Try starting the engine again.
If the engine will not start, see ”If your vehicle will not start”.
CAUTION
If the engine is not running, the power assist for the brakes and
steering will not work, so steering and braking will be much
harder than usual.
IF YOUR VEHICLE WILL NOT
START
(a) Simple checks
Before making these checks, make sure you have followed the
correct starting procedure instructions in ”How to start the engine”
on page 159 and that you have sufficient fuel. Since your vehicle is
equipped with the engine immobiliser system, also check whether
the other keys will start the engine. If they work, your key may be
broken. Have the key checked at your Lexus dealer. If none of your
keys work, the system is possibly broken. Call your Lexus dealer.
See ”Keys” on page 8.If the engine is not turning over or is turning over too slowly
1. Check that the battery terminals are tight and clean.
2. If the battery terminals are O.K., switch on the interior light.
3. If the light is out, dim or goes out when the starter is cranked, the
battery is discharged. You may try jump starting. See ”(c) Jump
starting” for further instruction.
If the light is O.K., but the engine still will not start, it needs
adjustment or repair. Call a Lexus dealer, Roadside Assistance or
Customer Service Assistance. (See ”Foreword”.)
NOTICE
Do not pull or pushstart the vehicle. It may damage the
vehicle or cause a collision when the engine starts. Also the
threeway catalytic converter may overheat and become a fire
hazard.
If the engine turns over at its normal speed but will not start
1. The engine may be flooded because of repeated cranking. See
”(b) Starting a flooded engine” for further instructions.
2. If the engine still will not start, it needs adjustment or repair. Call
a Lexus dealer, Roadside Assistance or Customer Service
Assistance. (See ”Foreword”.)

IN CASE OF AN EMERGENCY
194
(b) Starting a flooded engine
If the engine will not start, your engine may be flooded because
of repeated cranking.
If this happens, turn the key to ”START” with the accelerator pedal
held down. Continue this operation for 30 seconds and then stop
cranking. Then try starting the engine with your foot off the
accelerator pedal.
If the engine does not start after 30 seconds of cranking, release the
key, wait a few minutes and try again.
If the engine still will not start, it needs adjustment or repair. Call a
Lexus dealer. Roadside Assistance or Customer Service Assistance.
(See ”Foreword”.)
NOTICE
Do not crank for more than 30 seconds at a time. This may
overheat the starter and wiring systems.
(c) Jump starting
To avoid serious personal injury and damage to your vehicle
which might result from battery explosion, acid burns, electrical
burns, or damaged electronic components, these instructions
must be followed precisely.
If you are unsure about how to follow this procedure, we strongly
recommend that you seek help from your Lexus dealer, Roadside
Assistance or Customer Service Assistance. (See ”Foreword”.).
CAUTION
Batteries contain sulfuric acid which is poisonous and
corrosive. Wear protective safety glasses when jump
starting, and avoid spilling acid on your skin, clothing, or
vehicle.
If you should accidentally get acid on yourself or in your
eyes, remove any contaminated clothing and flush the
affected area with water immediately. Then get immediate
medical attention. If possible, continue to apply water with
a sponge or cloth while en route to the medical office.
The gas normally produced by a battery will explode if a
flame or spark is brought near. Use only standardized
jumper cables and do not smoke or light a match while
jump starting.
NOTICE
The battery used for boosting must be 12 V. Do not jump start
unless you are sure that the booster battery is correct.

IN CASE OF AN EMERGENCY
196
CAUTION
When making the connections, to avoid serious injury, do not
lean over the battery or accidentally let the jumper cables or
clamps touch anything except the correct battery terminals or
the ground.
5. Start your engine in the normal way. After starting, run it at about
2000 rpm for several minutes with the accelerator pedal lightly
depressed.
6. Carefully disconnect the cables in the exact reverse order: the
negative cable and then the positive cable.
7. Carefully dispose of the battery cover cloths which may now
contain sulfuric acid.
8. If removed, replace all the battery vent plugs.
If the cause of your battery discharging is not apparent (for example,
lights left on), you should have it checked.
IF YOUR VEHICLE OVERHEATS
If your engine coolant temperature gauge indicates overheating,
if you experience a loss of power, or if you hear a loud knocking
or pinging noise, the engine has probably overheated.
When the engine overheats
Pull safely off the road, stop the vehicle and turn on your emergency
flashers. Put the transmission in ”P” and apply the parking brake.
A: If steam is coming from your engine:
Turn off the engine. Leave the hood closed until there is no sign of
steam or coolant. Your engine could have been seriously damaged
already. Call your Lexus dealer for assistance.
CAUTION
To help avoid personal injury, keep the hood closed until there
is no steam. Escaping steam or coolant is sign of very high
pressure.

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.

INDEX (C E)
279
Consumer information
Uniform tire quality grading 244. . . . . . . . . . .
Controls, Instrument panel Pictorial index. . . . . .
Cooling system
Coolant level 233. . . . . . . . . . . . . . . . . . . . . . .
Engine overheating 196. . . . . . . . . . . . . . . . . .
Radiator and reservoir 233. . . . . . . . . . . . . . . .
Radiator cap 196. . . . . . . . . . . . . . . . . . . . . . .
Winter driving tips 182. . . . . . . . . . . . . . . . . . .
Corrosion prevention 270
Cruise control 168. . . . . . . . . . . . . . . . . . . . . . . .
Cruise information 42. . . . . . . . . . . . . . . . . . . . .
Cup holder 56. . . . . . . . . . . . . . . . . . . . . . . . . . . D
Defogger, Rear window 27. . . . . . . . . . . . . . . . .
Dimmer switch, Headlight 5, 24. . . . . . . . . . . .
Directional signals 5, 24. . . . . . . . . . . . . . . . . . .
Discharge warning light 39. . . . . . . . . . . . . . . . .
Does your vehicle need repairing? 217. . . . . . . .
Doityourself maintenance 221. . . . . . . . . . . .
Door locks 18. . . . . . . . . . . . . . . . . . . . . . . . . . .
Driver’s seat 2, 70. . . . . . . . . . . . . . . . . . . . . . . .
Driving
Automatic transmission 160. . . . . . . . . . . . . . .
Driving tips 180. . . . . . . . . . . . . . . . . . . . . . . .
Driving position memory system 113. . . . . . . . . .
Driving tips
Driving tips in various conditions 181. . . . . . .
Driving with an automatic
transmission 160. . . . . . . . . . . . . . . . . . . . . .
Economical driving 189. . . . . . . . . . . . . . . . . .
Good braking practice 176. . . . . . . . . . . . . . . .
Good driving practice 166
Winter driving tips 182. . . . . . . . . . . . . . . . . . .
During breakin 181. . . . . . . . . . . . . . . . . . . . . .
E
Economical driving .
Saving money on both fuel and
repairs 189. . . . . . . . . .
Electrical system
Battery 253. 257. . . . . . . . . . . . . . . . . . . . . . . .
Fuse locations 249. . . . . . . . . . . . . . . . . . . . . .
Fuses 249, 258, 260. . . . . . . . . . . . . . . . . . . . .
Spark plugs 226. . . . . . . . . . . . . . . . . . . . . . . .
Electronic throttle control system 167. . . . . . . .
Emergency flasher switch 31. . . . . . . . . . . . . . .
Emergency, in case of
Blown fuse 259. . . . . . . . . . . . . . . . . . . . . . . .
Emergency flasher switch 31. . . . . . . . . . . . . .
Flat tire 197. . . . . . . . . . . . . . . . . . . . . . . . . . .
If you lose your keys 210
If your vehicle needs to be towed 205. . . . . . .
If your vehicle will not start 193. . . . . . . . . . .
Jump starting 194. . . . . . . . . . . . . . . . . . . . . . .
Overheating 196. . . . . . . . . . . . . . . . . . . . . . . .
Towing 205. . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine
Antifreeze 233. . . . . . . . . . . . . . . . . . . . . . . . .
Before starting the engine 157. . . . . . . . . . . . .