Jeep 2009 Wrangler - Owner Manual - Manual (Page 421)

NOTE: Mixing engine coolant (antifreeze) types will
decrease the life of the engine coolant (antifreeze) and
will require more frequent engine coolant (antifreeze)
changes.
Cooling System Pressure Cap
The cap must be fully tightened to prevent loss of engine
coolant (antifreeze), and to ensure that engine coolant
(antifreeze) will return to the radiator from the coolant
reserve tank.
The cap should be inspected and cleaned if there is any
accumulation of foreign material on the sealing surfaces.
WARNING!
The warning words DO NOT OPEN HOT on the
cooling system pressure cap are a safety precaution.
Never add engine coolant (antifreeze) when the en-
gine is overheated. Do not loosen or remove the cap
to cool an overheated engine. Heat causes pressure to
build up in the cooling system. To prevent scalding
or injury, do not remove the pressure cap while the
system is hot or under pressure.
Disposal of Used Engine Coolant
Used ethylene glycol based engine coolant (antifreeze) is
a regulated substance requiring proper disposal. Check
with your local authorities to determine the disposal
rules for your community. To prevent ingestion by ani-
mals or children, do not store ethylene glycol based
engine coolant (antifreeze) in open containers or allow it
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MAINTAINING YOUR VEHICLE 419