229
2009
K
night
Chassis Information - 1
0
Radiator/Charge Air Cooler
The diesel
engine uses
compression
to ignite the
fuel/air charge.
To increase
compression
inside the
combustion
chamber
(resulting in increased power output) a
turbocharger is added to the engine. The
turbocharger is a paired housing assembly
with impellers inside each housing connected
by a common shaft. One impeller is propelled
by the engine exhaust which drives the other
impeller. The function of the other impeller is
to increase compression inside the combustion
chamber by forcing air into the intake
manifold.
This process works well, however, the
intake air charge is heated two different
ways: through convection by the exhaust
gases driving the turbocharger and when air
is compressed. This negative effect inside the
combustion chamber results in lost power
potential. Therefore, a Charge Air Cooler
(CAC) is installed to cool the intake air before
it enters the engine. The CAC performs the
same function as a radiator, cooling air instead
of liquid. Ambient air passing through the
CAC will cool the engine intake air charge.
After leaving the turbocharger, intake air
is compressed and heated to approximately
300º to 375º F., depending on the engine load
and throttle position. Before air enters the
intake manifold, the CAC cools the intake
air temperature to the engine manufacturer
specifications. Lowered intake air temperatures
reduce exhaust emissions, improve fuel
economy and increase horsepower. The CAC
will continually expand and contract up to ¼”
as throttle increases and decreases.
Cleaning and Maintenance:
Regular maintenance includes draining
the engine coolant, flushing/cleaning
the cooling system, inspecting the
water pump standpipe, replacing
the thermostat, gasket and seal, and
replacing the coolant and SCA element.
Inspect
the charge air cooler every
six months and remove dirt and
debris that may block the fins. If the
motorhome develops an oil leak, there
is a possibility that the oil will coat the
fins of the CAC. Dust will adhere to
the oil film, clog the fins and reduce
cooling efficiency. 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 fins. 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, with minimum
water pressure, standing back a
distance to avoid bending the fins.
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.
Coolant Hoses:
Inspect coolant hoses and connections when
checking engine or transmission fluids. Look
for any signs of chaffing at hose restraints
or sharp edges. Indications that hoses have
reached the end of service life include cracking
or swelling around clamps and connections.
Oil leaks can also deteriorate hoses.
Overheating can be caused by a collapsed
hose or a clog caused by rubber shedding from
a rotten hose. Replace any hose found to be
cracked, swollen or damaged. Connections
should be inspected periodically and hose
clamps tightened.
Every 12 months:
Inspect all hoses, clamps, and fittings for
leaks due to cracking, softness, and loose
clamps/fittings. Look for signs of fluid leaks,
damaged end fittings, ballooning, chafed,
kinked, or crushed hoses, and loose clamps
and fittings. Correct any deficiencies found.
090388c
090452
Representation of Radiator and
Charge Air Cooler
Representation of back of Radiator
Summary of Contents for 2009 Knight
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Page 46: ...42 2009 knight Driving Safety 2 Weighing Procedure Worksheet Example Worksheet 020255b conv...
Page 47: ...43 2009 knight Driving Safety 2 Weight Record Sheet Actual Worksheet 020255b 020263...
Page 52: ...48 2009 knight Driving Safety 2 Notes...
Page 152: ...148 2009 knight Water Systems 6 Notes...
Page 182: ...178 2009 knight Electrical Systems House 8 Notes...
Page 201: ...197 2009 knight Electrical Systems Chassis 9 engine no start flow chart...
Page 202: ...198 2009 knight Electrical Systems Chassis 9 Notes...
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Page 260: ...256 2009 knight Index Notes...