Diesel Exhaust Fluid; Cooling System - Jeep Grand Cherokee 4x2 2019 Supplement Manual

62 SERVICING AND MAINTENANCE
WARNING!
A hot exhaust system can start a fire if you park over
materials that can burn. Such materials might be grass
or leaves coming into contact with your exhaust sys-
tem. Do not park or operate your vehicle in areas where
your exhaust system can contact anything that can
burn.

Diesel Exhaust Fluid

Diesel Exhaust Fluid (DEF) sometimes known simply by
the name of its active component, UREA—is a key compo-
nent of selective catalytic reduction (SCR) systems, which
help diesel vehicles meet stringent emission regulations.
DEF is a liquid reducing agent that reacts with engine
exhaust in the presence of a catalyst to convert smog-
forming nitrogen oxides (NOx) into harmless nitrogen and
water vapor.
Refer to "Fluids And Lubricants" in "Technical Specifica-
tions" for further information.

Cooling System

WARNING!
• You or others can be badly burned by hot engine
coolant (antifreeze) or steam from your radiator. If
you see or hear steam coming from under the hood,
do not open the hood until the radiator has had time
to cool. Never open a cooling system pressure cap
when the radiator or coolant bottle is hot.
• Keep hands, tools, clothing, and jewelry away from
the radiator cooling fan when the hood is raised. The
fan starts automatically and may start at any time,
whether the engine is running or not.
• When working near the radiator cooling fan, discon-
nect the fan motor lead or turn the ignition to the
OFF mode. The fan is temperature controlled and can
start at any time the ignition is in the ON mode.
Engine Coolant Checks
Check the engine coolant (antifreeze) protection every 12
months (before the onset of freezing weather, where appli-
cable). If the engine coolant (antifreeze) is dirty, the system
should be drained, flushed, and refilled with fresh OAT
coolant (conforming to MS.90032) by an authorized dealer.