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Cooling System
The cooling system allows the engine to maintain the
correct working temperature.
When you decide it is safe to lift the hood, here is what
you will see:
A. Electric Engine Cooling Fan(s) (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.
{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.
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.
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{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 surge tank
pressure cap — even a little — they can come
out at high speed. Never turn the cap when the
cooling system, including the surge tank pressure
cap, is hot. Wait for the cooling system and surge
tank pressure cap to cool if you ever have to turn
the pressure cap.
If coolant is needed, add the proper DEX-COOL
®
coolant mixture at the coolant surge tank.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 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.
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.
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 5-32.
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Page 446 of 490

Additional Required Services (cont’d)
Service and Miles (Kilometers)25,000
(40 000)50,000
(80 000)75,000
(120 000)100,000
(160 000)125,000
(200 000)150,000
(240 000)
CTS-V Only: Inspect supercharger drive
belt.See footnote (m).•
If using DOT-4 brake uid, change brake
uid at a regular maintenance service
every two years.See footnote (j).
Maintenance Footnotes
(a)Visually inspect brake lines and hoses for proper
hook-up, binding, leaks, cracks, chafing, etc. Inspect
disc brake pads for wear and rotors for surface
condition. Inspect other brake parts, including calipers,
parking brake, etc.
(b)Visually inspect front and rear suspension and
steering system for damaged, loose, or missing parts or
signs of wear. Inspect power steering lines and hoses
for proper hook-up, binding, leaks, cracks, chafing, etc.
(c)Visually inspect hoses and have them replaced if they
are cracked, swollen, or deteriorated. Inspect all pipes,
fittings and clamps; replace with genuine parts as
needed. To help ensure proper operation, a pressure test
of the cooling system and pressure cap and cleaning the
outside of the radiator and air conditioning condenser is
recommended at least once a year.(d)Inspect wiper blades for wear, cracking, or
contamination. Clean the windshield and wiper blades, if
contaminated. Replace wiper blades that are worn or
damaged. See Windshield Wiper Blade Replacement on
page 5-59 and Windshield and Wiper Blades on
page 5-111 for more information.
(e)Make sure the safety belt reminder light and safety
belt assemblies are working properly. Look for any other
loose or damaged safety belt system parts. If you see
anything that might keep a safety belt system from doing
its job, have it repaired. Have any torn or frayed safety
belts replaced. Also see Checking the Restraint Systems
on page 1-74.
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(f)Lubricate all key lock cylinders. Lubricate all body door
hinges. Lubricate all hinges and latches, including those
for the hood, rear compartment, console door, and any
folding seat hardware. More frequent lubrication may be
required when exposed to a corrosive environment.
Applying silicone grease on weatherstrips with a clean
cloth will make them last longer, seal better, and not stick
or squeak.
(g)If driving regularly under dusty conditions, the filter
may require replacement more often.
(h)Change automatic transmission fluid and filter if the
vehicle is mainly driven under one or more of these
conditions:
In heavy city traffic where the outside temperature
regularly reaches 90°F (32°C) or higher.
In hilly or mountainous terrain.
When doing frequent trailer towing.
Uses such as high performance operation.(i)Drain, flush, and refill cooling system. This service can
be complex; you should have your dealer/retailer perform
this service. See Engine Coolant on page 5-32 for what to
use. Inspect hoses. Clean radiator, condenser, pressure
cap, and filler neck. Pressure test the cooling system and
pressure cap.
(j)If using DOT-4 brake fluid only: Drain, flush, and refill
brake hydraulic system at a regular maintenance service
every two years. This service can be complex; you should
have your dealer/retailer perform this service. See Brakes
on page 5-42.
(k)A fluid loss in any vehicle system could indicate a
problem. Have the system inspected and repaired
and the fluid level checked. Add fluid if needed.
(l)If driving regularly under dusty conditions, inspect the
filter at each engine oil change.
(m)Visually inspect belt for fraying, excessive cracks, or
obvious damage. Replace belt if necessary.
6-9