GMC 1996 Sierra Owner's Manual page 261

Noise Control System
The following information relates to compliance with
Federal noise emission standards for vehicles with a
Gross Vehicle Weight Rating (GVWR) of more than
10,000 Ibs. (4 536 kg). The Maintenance Schedule
booklet provides information on maintaining the noise
control system to minimize degradation of the noise
emission control system during the life of your vehicle.
The noise control system warranty is given in your
Warranty booklet.
These standards apply only to vehicles sold in the
United States.
Tampering With Noise Control
System Prohibited
Federal law prohibits the following acts or the
causing thereof:
1.
The removal o r rendering inoperative by any person,
other than for purposes of maintenance, repair or
replacement, of any device or element of design
incorporated into any new vehicle for the purpose of
noise control. prior to its sale or delivery to the
ultimate purchaser or while it is in use; or
2. The use of the vehicle after such device or element
of design has been removed or rendered inoperative
by any person.
Among those acts presumed to constitute tampering are
the acts listed below.
Insulation:
Removal of noise shields or underhood insulation.
Engine:
Removal or rendering engine speed governor (if so
equipped) inoperative so as to allow engine speed to
exceed manufkcturer specifications.
Fan and Drive:
0
Removal of fan clutch (if so equipped) or rendering
clutch inoperative.
Removal of fan shroud (if so equipped).
Air Intake:
Removal of air cleaner silencer
@
Reversing air cleaner cover.
Exhaust:
Removal of muffler and/or resonator.
Removal of exhaust pipes and exhaust pipe clamps.
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