WD Catalog 2018

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3-3 - -
Water Pump
Water Pump
Modern water pumps have a centrifugal design. Vanes or impellers in the
pump circulate the coolant. Figure 3-3 shows a cutaway view of a water pump
assembly.
FAN HUB
SHAFT SEAL
ASSEMBLY
WATER PUMP
BODY
METAL OR
PLASTIC IMPELLER
DRAIN
BEARING AND
SHAFT ASSEMBLY
Heater Components and Controls
The basic heater system components discussed in this section are:
1 . Heater Core
2 . Heater System Ducts
3 . Blower or Fan and Motor Assembly
4 . Hoses and Fittings
5 . Controls
1. Heater Core
Most heater cores are of tube and fin construction, with the inlet and
outlet on one end of the core. Hoses connect the core to the engine and are
held securely by hose clamps. Figure 3-4 illustrates a heater core. They
come in many sizes and shapes to meet cab space and heat energy
transfer requirements.
INLET AND OUTLET
ARE ATTACHED
TO MANIFOLD
ON THIS CORE
TUBE AND FIN
CONSTRUCTION
Figure 3-3
This cutaway drawing
shows the main components
of a water pump. Vane or
impeller type pumps work
best at high speed. Keep in
mind that the speed of the
pump is in proportion to
engine RPM.
Figure 3-4
In the heater core heat
energy moves from the hot
engine coolant to the air in
the truck cab. Cores come in
all sizes and shapes to meet
heat transfer needs.