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If you get the overheat warning with no sign of
steam, try this for a minute or so:
1. In heavy traffic, let the engine idle in
NEUTRAL (N) while stopped. If it is safe to do
so, pull off the road, shift to PARK (P) or
NEUTRAL (N) and let the engine idle.
2. Set the climate controls to the highest heat
setting and fan speed and open the windows,
as necessary.
If the coolant warning light is not on or the coolant
temperature gage does not indicate the engine
is overheating, you can drive. Just to be safe, drive
slower for about 10 minutes. If the warnings do
not come back on, drive normally.
If the warnings continue and you have not stopped,
pull over, stop, and park the vehicle right away.
If there is still no sign of steam, idle the engine for
three minutes while parked. If the warnings are
still indicated, turn off the engine and get everyone
out of the vehicle until it cools down. Also, see
“Overheated Engine Protection Operating Mode”
later in this section.
You might decide not to lift the hood but to get
service help right away.Overheated Engine Protection
Operating Mode
This operating mode allows your vehicle to be
driven to a safe place in an emergency. Should an
overheated engine condition exist, an overheat
protection mode which alternates ring groups of
cylinders helps prevent engine damage. In this
mode, you will notice a loss in power and engine
performance. An engine overheat warning will
indicate that an overheat condition exists. Driving
extended miles (km) and/or towing a trailer in
the overheat protection mode should be avoided.
Notice:After driving in the overheated
engine protection operating mode, to avoid
engine damage, allow the engine to cool before
attempting any repair. The engine oil will be
severely degraded. Repair the cause of coolant
loss and change the oil. SeeEngine Oil on
page 380.
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Cooling System
When you decide it is safe to lift the hood, this is
what you will see:
A. Engine Cooling Fans
B. Coolant Surge Tank and Pressure CapSome vehicles may have an engine driven fan, as
well as the electric pusher fans which are
located behind the vehicle’s grille.
{CAUTION:
An electric engine cooling fan under the
hood can start up even when the engine
is not running and can injure you. Keep
hands, clothing, and tools away from any
underhood electric fan.
If the coolant inside the coolant surge tank is
boiling, do not do anything else until it cools down.
The vehicle should be parked on a level surface.
When the engine is cold, the coolant level
should be at or slightly above the FULL
COLD/FROID line on the side of the coolant surge
tank. If it is not, you may have a leak at the
pressure cap or in the radiator hoses, heater
hoses, radiator, water pump, or somewhere else
in the cooling system.
3.6L V6 Engine shown, 4.6L V8 and 4.4L V8 STS-V
Engines similar
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How to Add Coolant to the Coolant
Surge Tank
If you have not found a problem yet, check to see
if coolant is visible in the surge tank. If coolant
is visible but the coolant level is not at the FULL
COLD/FROID line on the side of the coolant
surge tank, add a 50/50 mixture of clean, drinkable
water and DEX-COOL
®coolant at the coolant
surge tank, but be sure the cooling system,
including the coolant surge tank pressure cap, is
cool before you do it. SeeEngine Coolant on
page 389for more information.
{CAUTION:
Steam and scalding liquids from a hot
cooling system can blow out and burn
you badly. They are under pressure, and if
you turn the coolant surge tank pressure
cap — even a little — they can come out at
high speed. Never turn the cap when the
cooling system, including the coolant
CAUTION: (Continued)
CAUTION: (Continued)
surge tank pressure cap, is hot. Wait for
the cooling system and coolant surge
tank pressure cap to cool if you ever have
to turn the pressure cap.
{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can
boil before the proper coolant mixture will.
Your vehicle’s coolant warning system is
set for the proper coolant mixture. With
plain water or the wrong mixture, your
engine could get too hot but you would
not get the overheat warning. Your engine
could catch re and you or others could
be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant.
398
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{CAUTION:
Turning the Intercooler System pressure
cap when the engine and intercooler are
hot can allow steam and scalding liquids
to blow out and burn you badly. Never
turn the Intercooler System pressure cap,
even a little, when the engine and
intercooler are hot.
{CAUTION:
Adding only plain water to your cooling
system can be dangerous. Plain water, or
some other liquid such as alcohol, can
boil before the proper coolant mixture will.
Your vehicle’s coolant warning system is
set for the proper coolant mixture. With
plain water or the wrong mixture, your
CAUTION: (Continued)
CAUTION: (Continued)
engine could get too hot but you would
not get the overheat warning. Your engine
could catch re and you or others could
be burned. Use a 50/50 mixture of clean,
drinkable water and DEX-COOL
®coolant.
Notice:In cold weather, water can freeze and
crack the engine, radiator, heater core and
other parts. Use the recommended coolant and
the proper coolant mixture.
{CAUTION:
You can be burned if you spill coolant on
hot engine parts. Coolant contains
ethylene glycol and it will burn if the
engine parts are hot enough. Do not spill
coolant on a hot engine.
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