2008 CADILLAC CTS Owners Manual

Adding Coolant
If more coolant is needed, add the proper DEX-COOL®
coolant mixture at the surge tank, but only when the
engine is cool.
{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains eythylene glycol,
and it will burn if the engine parts are hot
enough. Do not spill coolant on a hot engine.
When replacing the pressure cap, make sure it is
hand-tight and fully seated.
Coolant Surge Tank Pressure Cap
Notice:If the pressure cap is not tightly installed,
coolant loss and possible engine damage may
occur. Be sure the cap is properly and tightly
secured.
The coolant surge tank pressure cap must be fully
installed on the coolant surge tank. SeeEngine
Compartment Overview on page 5-14for more
information on location.
Engine Overheating
There are two engine hot messages that may be
displayed in the Driver Information Center (DIC).
SeeDIC Warnings and Messages on page 3-56for
more information.
5-31

If Steam Is Coming From Your Engine
{CAUTION:
Steam from an overheated engine can burn
you badly, even if you just open the hood.
Stay away from the engine if you see or hear
steam coming from it. Turn it off and get
everyone away from the vehicle until it cools
down. Wait until there is no sign of steam or
coolant before you open the hood.
If you keep driving when the vehicles engine
is overheated, the liquids in it can catch re.
You or others could be badly burned. Stop
your engine if it overheats, and get out of
the vehicle until the engine is cool.
SeeOverheated Engine Protection Operating
Mode on page 5-33for information on driving
to a safe place in an emergency.Notice:If the engine catches re while driving
with no coolant, the vehicle can be badly damaged.
The costly repairs would not be covered by the
vehicle warranty. SeeOverheated Engine Protection
Operating Mode on page 5-33for information on
driving to a safe place in an emergency.If No Steam Is Coming From Your
Engine
An Engine Overheated Idle Engine warning, along with
low coolant, can indicate a serious problem.
If you get an Engine Overheated Idle Engine warning,
but see or hear no steam, the problem may not be
too serious. Sometimes the engine can get a little
too hot when you:
Climb a long hill on a hot day.
Stop after high-speed driving.
Idle for long periods in traffic.
Tow a trailer.
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If you get the Engine Overheated Idle Engine warning
with no sign of steam, try this for a minute or so:
1. In heavy traffic, let the engine idle in N (Neutral)
while stopped. If it is safe to do so, pull off the
road, shift to P (Park) or N (Neutral) 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 you no longer have the Engine Overheated Idle
Engine warning, you can drive. Just to be safe, drive
slower for about 10 minutes. If the warning does
not come back on, you can drive normally.
If the warning continues and you have not stopped,
pull over, stop, and park your vehicle right away.
If there is still no sign of steam, you can idle the engine
for three minutes while you are parked. If you still have
the warning,turn off the engine and get everyone out of
the vehicleuntil it cools down.
You may 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 a hot engine
condition exist, an overheat protection mode which
alternates ring groups of cylinders helps prevent engine
damage. In this mode, there is a loss in power and engine
performance. 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 5-16.
5-33

Cooling System
When you decide it is safe to lift the hood, here is what
you will see:
A. Electric Engine Cooling Fans (Out of View)
B. Coolant Surge Tank and Pressure Cap{CAUTION:
An electric engine cooling fan under the hood
can start up even when the engine is not
running and can cause injury. 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.
If the engine is warm or hot, the coolant level should be
at or above the FROID/FULL COLD line on the side of the
coolant surge tank. If the engine is cold, the coolant level
should be near the FROID/FULL COLD line on the side of
the coolant surge tank. If it is not, you could have a leak
at the pressure cap or in the radiator hoses, heater
hoses, radiator, water pump, or somewhere else in
the cooling system.
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{CAUTION:
Heater and radiator hoses, and other engine
parts, can be very hot. Do not touch them.
If you do, you can be burned.
Do not run the engine if there is a leak. If you
run the engine, it could lose all coolant. That
could cause an engine re, and you could be
burned. Get any leak xed before you drive the
vehicle.
If there seems to be no leak, with the engine on, check
to see if the electric engine cooling fans are running.
If the engine hot light is on, both fans should be running.
If they are not, your vehicle needs service.Notice:Engine damage from running your engine
without coolant is not covered by your warranty.
SeeOverheated Engine Protection Operating Mode
on page 5-33for information on driving to a safe
place in an emergency.
Notice:Using coolant other than DEX-COOL®can
cause premature engine, heater core, or radiator
corrosion. In addition, the engine coolant could
require changing sooner, at 30,000 miles (50 000 km)
or 24 months, whichever occurs rst. Any repairs
would not be covered by the vehicle warranty.
Always use DEX-COOL
®(silicate-free) coolant in
the vehicle.
5-35

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 FROID/FULL COLD 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 5-28for
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 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 the cooling system
can be dangerous. Plain water, or some other
liquid such as alcohol, can boil before the
proper coolant mixture will. The vehicle’s
coolant warning system is set for the proper
coolant mixture. With plain water or the wrong
mixture, the engine could get too hot but you
would not get the overheat warning. The 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.
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{CAUTION:
You can be burned if you spill coolant on hot
engine parts. Coolant contains eythylene glycol
and it will burn if the engine parts are hot
enough. Do not spill coolant on a hot engine.
If no coolant is visible in the surge tank, add coolant as
follows:
1. Remove the coolant surge tank pressure cap when
the cooling system, including the coolant surge tank
pressure cap and upper radiator hose, is no longer
hot. Turn the pressure cap slowly counterclockwise
about one-quarter turn and then stop.
If you hear a hiss, wait for that to stop. A hiss
means there is still some pressure left.2. Then keep turning the pressure cap slowly, and
remove it.
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3. Fill the coolant surge tank with the proper mixture,
to slightly above the FROID/FULL COLD line on the
side of the coolant surge tank.4. With the coolant surge tank pressure cap off, start
the engine and let it run until you can feel the upper
radiator hose getting hot. The upper radiator hose is
the top hose coming out of the radiator, on the
passenger’s side of the vehicle. Watch out for the
engine cooling fans.
By this time, the coolant level inside the coolant
surge tank may be lower. If the level is lower, add
more of the proper mixture to the coolant surge tank
until the level reaches the FROID/FULL COLD
line on the side of the coolant surge tank.
5. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
Recheck the coolant level in the bottle next time you
use your vehicle to insure the system is full when cold.
SeeEngine Coolant on page 5-28.
5-38