2004 Lexus GX470 engine overheat

GAUGES, METERS AND SERVICE REMINDER INDICATORS
52
ENGINE COOLANT
TEMPERATURE GAUGE

Normal range
The gauge indicates the engine coolant temperature when
the ignition switch is on. The engine operating
temperature will vary with changes in weather and engine
load.
If the needle points to the red zone or higher, stop your vehicle
and allow the engine to cool.
Your vehicle may overheat during severe operating conditions,
such as:
Driving up a long hill on a hot day.
Reducing speed or stopping after high speed driving.
Idling for a long period with the air conditioning on in
stop-and-go traffic.
Towing a trailer.It is not a malfunction even if the needle of the engine coolant
temperature gauge returns to Cº when the ignition switch is
turned to the STARTº.

GAUGES, METERS AND SERVICE REMINDER INDICATORS
53
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 overheatsº on page 443.

STARTING AND DRIVING
357
NOTICE
A large amount of unburned gases flowing into the
three-way catalytic converter may cause it to overheat
and create a fire hazard. To prevent this and other
damage, observe the following precautions:
Use only unleaded gasoline.
Do not drive with an extremely low fuel level; running
out of fuel could cause the engine to misfire, creating
an excessive load on the three-way catalytic
converter.
Do not allow the engine to run at idle speed for more
than 20 minutes.
Avoid racing the engine.
Do not push-start or pull-start your vehicle.
Do not turn off the ignition while the vehicle is
moving.
Keep your engine in good running order.
Malfunctions in the engine electrical system, electric
ignition system or fuel system could cause an
extremely high three-way catalytic converter
temperature.
If the engine becomes difficult to start or stalls
frequently, take your vehicle in for a check-up as
soon as possible. Remember, your Lexus dealer
knows your vehicle and its three-way catalytic
converter system best.

STARTING AND DRIVING
369
(c) Using the 3º, 2º and Lº positions
The 3º, 2º and Lº positions are used for strong engine braking
as described previously.
With the selector lever in 3º, 2º or Lº, you can start the vehicle
in motion as with the lever in Dº.
With the selector lever in 3º or 2º, the vehicle will start in first
gear and automatically shift to second gear.
With the selector lever in Lº, the transmission is engaged in
first gear.
NOTICE
Be careful not to over-rev the engine. Watch the
tachometer to keep engine rpm from going into the
red zone. The approximate maximum allowable
speed for each position is given below for your
reference:
Transmission Transfer
Lº Hº
3º 53 km/h (33 mph) 136 km/h (85 mph)
2º 36 km/h (22 mph) 93 km/h (58 mph)
Lº 21 km/h (13 mph) 54 km/h (33 mph)
Do not continue hill climbing or hard towing for a long
time in the 3º, 2º or Lº position. This may cause
severe automatic transmission damage from
overheating. To prevent such damage, 4º position
should be used in hill climbing or hard towing.

STARTING AND DRIVING
372When towing a trailer, in order to maintain efficient engine
braking and electrical charging performance, do not use
overdrive.
CAUTION
Always keep your foot on the brake pedal while stopped
with the engine running. This prevents the vehicle from
creeping.
NOTICE
Always use the brake pedal or parking brake to hold the
vehicle on an upgrade. Do not attempt to hold the
vehicle using the accelerator pedal, as this can cause
the transmission to overheat.

DRIVING TIPS
409
CAUTION
Before driving off, make sure the parking brake is
fully released and that the parking brake reminder
light is off.
Do not leave your vehicle unattended while the
engine is running.
Do not rest your foot on the brake pedal while driving.
It can cause dangerous overheating, needless wear,
and poor fuel economy.
To drive down a long or steep hill, reduce your speed
and downshift. Remember, if you ride the brakes
excessively, they may overheat and not work
properly. See page 368.
Be careful when accelerating, upshifting,
downshifting or braking on a slippery surface. The
abrupt change in engine speed, such as sudden
acceleration or engine braking, could cause the
vehicle to spin or skid.
Do not drive in excess of the speed limit. Even if the
legal speed limit permits it, do not drive over 140 km/h
(85 mph) unless your vehicle has high-speed
capability tires. Driving over 140 km/h (85 mph) may
result in tire failure, loss of control and possible
injury. Be sure to consult a tire dealer to determine
whether the tires on your vehicle are high-speed
capability tires or not before driving at such speeds.

DRIVING TIPS
428Remember that when making a turn, the trailer wheels will
be closer than the vehicle wheels to the inside of the turn.
Therefore, compensate for this by making a larger than
normal turning radius with your vehicle.
Crosswinds and rough roads will adversely affect handling
of your vehicle and trailer, causing sway. Pay attention to
the rear from time to time to prepare yourself for being
passed by large trucks or buses, which may cause your
vehicle and trailer to sway. If swaying happens, firmly grip
the steering wheel and reduce speed immediately but
gradually. Never increase speed. If it is necessary to
reduce speed, brake slowly. Steer straight ahead. If you
make no extreme correction with the steering or brakes,
your vehicle and trailer will stabilize.
Be careful when passing other vehicles. Passing requires
considerable distance. After passing a vehicle, do not forget
the length of your trailer and be sure you have plenty of room
before changing lanes.
In order to maintain efficient engine braking and electrical
charging performance, do not use overdrive. Transmission
must be 4º position.
Because 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 overheatsº on page 443.Always place wheel blocks under both the vehicle and trailer
wheels when parking. Apply the parking brake firmly. Put
the transmission in Pº. 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 Pº and turn off the engine.

DRIVING TIPS
429 When restarting out after parking on a slope:
1. With the transmission in Pº position, start the engine. Be
sure to keep the brake pedal depressed.
2. Shift into the 3º, 2º, Lº or Rº 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 vehicle-trailer 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.
HOW TO SAVE FUEL AND MAKE
YOUR VEHICLE LAST LONGER
Improving fuel economy is easy Ð 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 warm-up idling. Once the engine is
running smoothly, begin driving Ð but gently. Remember,
however, that on cold winter days this may take a little
longer.
Always keep the automatic transmission selector lever
in the Dº position when engine braking is not required.
Driving with the overdrive off will reduce the fuel economy.
(For details, see Automatic transmissionº on page 365.)
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 over-revving. Use a gear position suitable
for the road on which you are traveling.