Cadillac CTS 2018 Owner's Manual page 258

What to Use
Warning
Do not touch heater or radiator
hoses, or other engine parts. They
can be very hot and can burn you.
Do not run the engine if there is a
leak; all coolant could leak out.
That could cause an engine fire and
can burn you. Fix any leak before
driving the vehicle.
Use a 50/50 mixture of clean
drinkable water and DEX-COOL
coolant. This mixture:
Gives freezing protection down to
-37 °C (-34 °F), outside
temperature
Gives boiling protection up to
129 °C (265 °F), engine
temperature
Protects against rust and corrosion
Will not damage aluminium parts
Helps keep the proper engine
temperature
Caution
Do not use anything other than a
mix of DEX-COOL coolant that
meets GM Standard GMW3420 and
clean, drinkable water. Anything
else can cause damage to the
engine cooling system and the
vehicle, which would not be covered
by the vehicle warranty.
Never dispose of engine coolant by
putting it in the refuse, pouring it on
the ground, or into sewers, streams,
or bodies of water. Have the coolant
changed by an authorised service
centre, familiar with legal
requirements regarding used coolant
disposal. This will help protect the
environment and your health.
Checking Coolant
The vehicle must be on a level surface
when checking the coolant level.
VEHICLE CARE
It is normal to see coolant moving in
the upper coolant hose return line
when the engine is running. It is also
normal to see bubbles entering the
surge tank through the small hose.
Check to see if coolant is visible in the
coolant surge tank. If the coolant
inside the coolant surge tank is
boiling, do not do anything else until
it cools down.
It is normal for the coolant level in
the bottom chamber to rise and fall
with operating temperature and
ambient conditions. Coolant will
evaporate from the bottom chamber
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