Pontiac 2003 Aztek Owner's Manual page 319

Checking Coolant
Adding Coolant
If you need more coolant, add the proper DEX-COOL@
coolant mixture at the coolant recovery tank.
Turning the radiator pressure cap when the
engine and radiator are hot can allow steam
and scalding liquids to blow out and burn you
badly. With the coolant recovery tank, you will
almost never have to add coolant at the
radiator. Never turn the radiator pressure
cap
--
even a little
--
when the engine and
radiator are hot.
The engine coolant reservoir is located on the driver's
side of the vehicle, above the engine air cleaner/filter.
See Engine Compartment Overview on page 5-12
for more information on location.
The vehicle must be on a level surface. When your
engine is cold, the coolant level should be at the FULL
COLD mark, or a little higher. When your engine is
warm, the level should be above the FULL COLD mark
or a little higher.
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