Cadillac 1999 Eldorado, Owner'S Manual, Page: 269 / 344

yellow blue
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Thermostat
Engine coolant temperature is controlled by a thermostat
in the engine coolant system. The thermostat stops the
flow of coolant through the radiator until the coolant
reaches a preset temperature.
If your thermostat needs to be replaced, a GM
thermostat is recommended.
Engine Coolant
The cooling system in your vehicle is filled with
DEX
-
COOL
R
engine coolant. This coolant is designed
to remain in your vehicle for 5 years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
DEX
-
COOL
R
extended life coolant.
The following explains your cooling system and how
to add coolant when it is low. If you have a problem
with engine overheating, see “Engine Overheating” in
the Index.
A 50/50 mixture of clean, drinkable water and
DEX
-
COOL
R
coolant will:
D Give freezing protection down to
-
34
_F (
-
37
_C).
D Give boiling protection up to 265_F (129_C).
D Protect against rust and corrosion.
D Help keep the proper engine temperature.
D Let the warning lights and gages work as
they should.
NOTICE:
When adding coolant, it is important that you use
only DEX
-
COOL
R
(silicate
-
free) coolant.
If coolant other than DEX
-
COOL is added to the
system, premature engine, heater core or
radiator corrosion may result. In addition, the
engine coolant will require change sooner
--
at
30,000 miles (50 000 km) or 24 months,
whichever occurs first. Damage caused by the use
of coolant other than DEX
-
COOL
R
is not
covered by your new vehicle warranty.