Section 10 --- Chassis Information
The Executive 2005
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Inspect the radiator core and CAC for dirt and debris build-up. Wash any accumulations using
high-pressure water, being careful not to damage the fins from excessive pressure. Any grease or oil
build-up should first be treated with a non-caustic degreaser to ensure a thorough cleaning.
Coolant System - Thawing:
If the coolant system becomes frozen, the motorhome must be towed. Place the motorhome in a
warm area until completely thawed. If the engine is operated when the cooling system is frozen it
will result in engine overheating due to insufficient coolant circulation. Once thawed, check engine,
radiator and related components for damage caused by expansion of frozen coolant.
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 com-
mon shaft. One impeller is propelled by the engine exhaust, which drives the other impeller. The func-
tion 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 any time air is com-
pressed heat is produced. This has a negative effect inside the combustion chamber resulting in lost
power potential. Therefore, a Charge Air Cooler (CAC) is installed to cool the intake air before it
enters the engine. The CAC may be mounted to either the top or side of the radiator. The CAC per-
forms 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.
Visually inspect the charge air cooler, every six months, for dirt and debris that may be blocking
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 and eventually clog the fins, greatly reducing cooling effi-
ciency. When the oil leak is repaired, the CAC must be thoroughly cleaned.
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