Engine Coolant - Hummer H2 2009 Owner's Manual

5. 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. Watch out for the
engine cooling fan.
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 mark.
6. Then replace the pressure cap. Be sure the
pressure cap is hand-tight and fully seated.
7. Verify coolant level after engine is shut off and the
coolant is cold. If necessary, repeat coolant fill
procedure steps 1 through 7.

Engine Coolant

The cooling system in the vehicle is filled with
®
DEX-COOL engine coolant. This coolant is designed
to remain in the vehicle for five years or 150,000 miles
(240 000 km), whichever occurs first, if you add only
®
DEX-COOL extended life coolant.
The following explains the cooling system and how to add
coolant when it is low. If you have a problem with engine
overheating, see Engine Overheating on page 5-33.
A 50/50 mixture of clean, drinkable water and
®
DEX-COOL coolant will:
Give freezing protection down to −34°F (−37°C).
•
•
Give boiling protection up to 265°F (129°C).
•
Protect against rust and corrosion.
•
Help keep the proper engine temperature.
•
Let the warning lights and gages work as they
should.
Notice: Using coolant other than DEX-COOL
cause premature engine, heater core, or radiator
corrosion. In addition, the engine coolant may
require changing sooner, at the first maintenance
service after each 30,000 miles (50 000 km) or
24 months, whichever occurs first. Any repairs would
not be covered by the vehicle warranty. Always use
®
DEX-COOL (silicate-free) coolant in the vehicle.
®
can
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