Brake - Auxiliary (Engine Brake) - Holiday Rambler Imperial 2008 Owner's Manual

Cleaning and Maintenance:
Inspect the charge air cooler every
week and remove dirt and debris that
may block the fi ns. If the motorhome
develops an oil leak, there is a possibility
that the oil will coat the fi ns of the CAC.
Dust will adhere to the oil fi lm, clog the
fi ns and reduce cooling effi ciency. When
the oil leak is repaired, the CAC must be
thoroughly cleaned.
During each oil change inspect the
engine side of the radiator/CAC
assembly for foreign objects that may
cause restriction.
Spraying degreaser on the charge air
cooler, as well as using a steam cleaner,
will not damage the CAC. However,
pressure washer and steam cleaner
nozzles placed too close to the CAC
can bend the fi ns. The recommended
cleaning procedure for the CAC and the
radiator is to use a bucket of mild soap
and water. Carefully wash with a bristle
brush then rinse using a garden hose,
with minimum water pressure, standing
back a distance to avoid bending the fi ns.
When performing maintenance, it is also
necessary to inspect other components
of the cooling system. The charge
air cooler and radiator also requires
an inspection for cracks, broken
welds, secure mounting, and general
cleanliness.
Every 12 months:
Inspect all hoses, clamps, and fi ttings for
leaks due to cracking, softness, and loose
clamps/fi ttings. Look for signs of fl uid leaks,
damaged end fi ttings, ballooning, chafed,
kinked, or crushed hoses, and loose clamps and
fi ttings. Correct any defi ciencies found.

BRAKE - AUXILIARY (Engine Brake)

Auxiliary braking systems are designed to
supplement the standard air brake system.
The engine brake is not designed to bring the
motorhome to a complete stop; however, it can
assist in controlling the speed of the motorhome.
Use of the engine braking system can extend the
service life of pads, shoes, rotors and drums.
The engine brake operates on a different
principle than an exhaust brake. An engine
brake functions by releasing compression.
The effect of the engine brake increases with
speed. When the engine brake is activated
the transmission automatically optimizes
downshifts, utilizing the gear selected to
maximize the effectiveness of the engine brake.
When the engine brake activates, an electrical
signal is sent to the ECM (electronic control
module). The ECM controls a hydraulic circuit
that opens the exhaust valves near the end of
the compression stroke. The potential engine
braking power depends on turbocharger boost
pressure, engine speed and gear selection.
20 0 8 I M P E R I AL
CHASSIS INFORMATION — 10
Use the engine brake when descending a hill
or off ramp. Turn on the Engine Brake switch
then select either the HI or LOW switch setting.
The engine brake will activate when the throttle
is released to the idle position.
NOTE:
Activating the Engine Brake switch
will cancel cruise control. Vorad Smart
Cruise will engage the engine brake
should the vehicle ahead decelerate or
when cruise set speed exceeds cruise
speed parameters. Refer to the OEM
engine manual for more information.
NOTE:
The engine brake is designed to
supplement the service brakes. The
engine brake will not bring the
motorhome to a stop. Use of the engine
brake can help increase the service life
of the service brakes.
NOTE:
Idle the engine three to five minutes
at approximately 1000 RPM to warm
the engine before activating the engine
brake. DO NOT operate the engine
brake until engine oil temperature is
above 30º C. (86º F.).
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