49–00 Safety Precautions
Safety Precautions in this section apply to all
procedures within this group.
DANGER
When working on the vehicle, shut down the en-
gine, set the parking brake, and chock the tires.
Before working under the vehicle, always place
jack stands under the frame rails to ensure the
vehicle can not drop. Failure to follow these steps
could result in serious personal injury or death.
49–01 Exhaust System
Inspection (Noise
Emission Control)
In addition to inspecting the exhaust system at the
scheduled maintenance interval, inspect the exhaust
system if the noise level of the vehicle has in-
creased. Freightliner Trucks recommends replacing
parts that show leakage, wear, or damage, with
genuine Freightliner parts.
It is a violation of US federal law to alter exhaust
plumbing or aftertreatment in any way that would
bring the engine out of compliance with certification
requirements. (Ref: 42 U.S.C. S7522(a) (3).) It is the
owner’s responsibility to maintain the vehicle so that
it conforms to EPA regulations.
Definitions of ATS Terms
Refer to the following list of definitions of ATS terms
and components.
•
Aftertreatment System (ATS)—the entire ex-
haust system from the turbocharger to the ex-
haust stack or tail pipe.
•
Aftertreatment Device (ATD)—a housing that
contains the DOC and DPF (also the SCR and
the mixing tube in one-box systems).
•
BlueTec®—Daimler’s proprietary SCR technol-
ogy.
•
Diesel Oxidation Catalyst (DOC)—a flow-
through device that oxidizes soot in the ATD.
•
Diesel Particulate Filter (DPF)—a component in
the ATD that traps soot from the exhaust gas.
•
Diesel Exhaust Fluid (DEF)—the chemical agent
that reacts with the exhaust gases in the SCR
to reduce NOx.
•
DEF Pump—filters and supplies DEF to the
DEF metering unit.
•
DEF Tank—holds DEF and regulates its tem-
perature.
•
DEF Metering Unit—mixes DEF with com-
pressed air, and meters this mixture into the
exhaust flow via an injection nozzle.
•
SCR Catalyst—the housing containing a treated
ceramic flow-through block where the DEF and
exhaust gases undergo selective catalytic re-
duction (SCR).
•
Selective Catalytic Reduction (SCR)—a process
used to reduce NOx emissions.
EPA10 and Newer Exhaust
System Inspection
To meet EPA10 emissions regulations for vehicles
domiciled in the USA or Canada, engines manufac-
tured after December 31, 2009 are equipped with an
emission aftertreatment system. Vehicles domiciled
outside of the USA and Canada may not have after-
treatment equipment, depending upon local statutory
emissions guidelines.
IMPORTANT: The aftertreatment device (ATD),
which is part of the aftertreatment system (ATS),
requires special attention during regularly
scheduled maintenance inspections. No leaks
are allowed anywhere in the system. If any dis-
crepancies are discovered, refer to the engine
manufacturer’s service literature for repair in-
structions.
1.
Check for leakage at the clamp that attaches the
exhaust pipe to the turbocharger exhaust outlet.
If leakage exists, tighten the nut on the clamp to
the required torque. If leakage persists, install a
new clamp.
2.
Check the exhaust pipe, bellows, and each ex-
haust seal clamp for leakage, wear, cracks, or
damage. Replace damaged components as
needed. If leakage exists at a clamp, tighten the
nuts to the required torque. If leakage persists,
install a new exhaust seal clamp. Do not reuse
seal clamps. Once a seal clamp is loosened or
removed, it must be replaced.
Exhaust
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