Base Engine Operation
03
120
12
RG,RG34710,67 –19–30SEP97–2/2
The head gasket must form an air-tight seal between
cylinder liners and cylinder head that can withstand the
temperatures and pressures of the combustion
process. The gasket must also form a liquid-tight seal
between the cylinder head and cylinder block to retain
coolant and oil in their respective passages. The
gasket is constructed of a solid steel core (F) covered
by perforated steel core (J) and graphite body (I). The
surface of gasket is treated to improve liquid sealing
and anti-stick characteristics. A fire ring combustion
seal (G) is located at each cylinder bore and is held in
place by a U-shaped stainless steel flange (H).
The cylinder head and block must be flat to provide an
even clamping pressure over the entire surface of
gasket, and must have the proper surface finish to
keep gasket material form moving in the joint. Dowel
pins (C) are used to properly locate head gasket on
block.
The cylinder liners (D) must protrude evenly from top
of cylinder block the specified amount to provide
adequate clamping force on fire ring of each cylinder.
The cap screws (B) must be proper length, made of
proper material, and be tightened to proper torque in
order to provide an adequate clamp load between
other joint components.
Each of the above components contributes to the
integrity of the head gasket joint. If any of these
components do not conform to specification, gasket
joint may fail resulting in combustion leaks, coolant
leaks, or oil leaks.
Operating conditions such as coolant, oil, and
combustion temperatures, and combustion pressures
can reduce the ability of the head gasket joint to
function properly. Failure of head gasket and mating
parts may occur when coolant and oil temperatures
become excessive, or when abnormally high
combustion temperatures and pressure persist.
RG,RG34710,1522 –19–30SEP97–1/1
Intake and Exhaust System Operation
Engine suction draws dust-laden outside air through an
air inlet stack into the air cleaner. Air is filtered through
dry-type primary and final filter elements in the air
cleaner canister. Clean air travels through the intake
air hose to the turbocharger, through the air-to-air
aftercooler, through the air/fuel mixing elbow, and into
the intake manifold.
Exhaust, as it is expelled out of the exhaust manifold,
drives the turbocharger to deliver a larger quantity of
air to meet the engine requirements than what could
be delivered under naturally aspirated
(non-turbocharged) conditions.
On some engines, an air-to-air aftercooler cools the
turbocharger compressor discharge air by routing it
through a heat exchanger before it enters the engine.
The heat exchanger uses no liquid coolant but relies
on air flow to cool the charge air.
On some engines, the aftercooler functions as a heat
exchanger. Engine coolant circulates through the
aftercooler core and carries heat out of the aftercooler.
CTM100 (06APR04)
03-120-12
P
OWER
T
ECH
10.5 L & 12.5 L Diesel Engines
040604
PN=344
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