SERVICING AND MAINTENANCE
379
(Continued)
D
IESEL
E
XHAUST
F
LUID
Diesel Exhaust Fluid (DEF) sometimes known
simply by the name of its active component,
UREA—is a key component 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.
For further information
A
CCESSORY
D
RIVE
B
ELT
I
NSPECTION
When inspecting accessory drive belts, small
cracks that run across the ribbed surface of the
belt, from rib to rib, are considered normal.
These are not a reason to replace a belt.
However, cracks running along a rib (not across)
are not normal. Any belt with cracks running
along a rib must be replaced. Also have the belt
replaced if it has excessive wear, frayed cords,
or severe glazing.
Accessory Belt (Serpentine Belt)
Conditions that would require replacement:
Rib chunking (one or more ribs has sepa
-
rated from belt body)
Rib or belt wear
Longitudinal belt cracking (cracks between
two ribs)
Belt slips
“Groove jumping" (belt does not maintain
correct position on pulley)
Belt broken
Noise (objectionable squeal, squeak, or
rumble is heard or felt while drive belt is in
operation)
NOTE:
Identify and correct problem before new belt is
installed.
WARNING!
A hot exhaust system can start a fire if you
park over materials that can burn. Such mate
-
rials might be grass or leaves coming into
contact with your exhaust system. Do not
park or operate your vehicle in areas where
your exhaust system can contact anything
that can burn.
WARNING!
Do not attempt to inspect an accessory
drive belt with vehicle running.
When working near the radiator cooling fan,
disconnect the fan motor lead. The fan is
temperature controlled and can start at any
time regardless of ignition mode. You could
be injured by the moving fan blades.
You can be badly injured working on or
around a motor vehicle. Only do service
work for which you have the knowledge and
the proper equipment. If you have any
doubt about your ability to perform a
service job, take your vehicle to a compe
-
tent mechanic.
WARNING!
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