CADILLAC STS 2008 1.G Owners Manual
Manufacturer: CADILLAC, Model Year: 2008, Model line: STS, Model: CADILLAC STS 2008 1.GPages: 500, PDF Size: 5.81 MB
Page 351 of 500

{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 is overheating, 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. See
Overheated Engine Protection Operating Mode on
page 5-31for information on driving to a safe place
in an emergency.
Notice:Using coolant other than DEX-COOL®may
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 warranty. Always
use DEX-COOL
®(silicate-free) coolant in the vehicle.
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Page 352 of 500

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 5-25for 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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Page 353 of 500

{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.
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 of a turn.
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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Page 354 of 500

3. Fill the coolant surge tank with the proper
DEX-COOL®coolant mixture, to slightly above the
FULL COLD/FROID 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 largest of the hoses which comes out of
the radiator, on the passenger 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 FULL COLD/FROID
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.
Start the engine and allow it to warm up.
How to Add Coolant to the Intercooler
System Fill Neck (4.4L V8 STS-V
Engine Only)
If you have not found a problem yet, turn the engine off
and allow it to cool down, then check to see if coolant
is visible within the horizontal tube section of the
ll neck. If coolant is not visible, add a 50/50 mixture of
clean, drinkable water and DEX-COOL
®coolant to
the ll neck. Be sure the Intercooler System, including
the Intercooler System pressure cap, is cool before
doing so. SeeEngine Coolant on page 5-25for more
information.
5-36
Page 355 of 500

{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 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.
{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.
5-37
Page 356 of 500

1. Remove the Intercooler System pressure cap when
the Intercooler System, including the upper
intercooler hoses, are no longer hot. Turn the
pressure cap slowly counterclockwise about
one-quarter of a turn. If you hear a hiss, wait for
that to stop. This allows any pressure still left to be
vented.2. Then keep turning the pressure cap slowly, and
remove it.
3. Add the proper DEX-COOL
®coolant mixture to the
ll neck, until the coolant reaches the COLD FILL
line on the ll neck.
4. With the Intercooler System pressure cap off, start
the engine and let it run for a couple of minutes.
Then turn the engine off. By this time, the coolant
level inside the ll neck may be lower. If the
level drops to where coolant is no longer visible in
the horizontal tube section of the ll neck, with
the engine off add more of the DEX-COOL
®coolant
mixture to the ll neck until the level is again
visible in the horizontal tube section.
5. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
If the coolant is not at the proper level when the
system cools down again, see your dealer.
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