General
This manual describes the cooling system and the
removal and replacement procedures for its main
components.
The cooling system for the transmission is
described in Transmission 1300SRM1455.
The hydraulic control system for the K007, J019,
and A238 truck is described in Hydraulic Control
System 2200SRM1481.
COOLING SYSTEM DESCRIPTION
When the truck operates, heat is generated in vari-
ous truck components. Most of these components
can sufficiently dissipate the generated heat to the
surrounding air. A cooling system is required for
the engine, hydraulic system and the transmission,
because of the big and fluctuating volume of heat to
be dissipated and the need for a controlled operat-
ing temperature. Each of these systems has its own
cooling core.
The cores are mounted in a cooling core assembly
(together with the charge air cooler). In this assem-
bly, the heat is dissipated by an airflow which is
pulled through the cooling cores by a belt-driven
fan.
Cooling Cores
The cooling cores transfer the heat from the fluid
inside to the air outside. The fluid (coolant or oil) or
charge air is in contact with the core, which trans-
fers its heat to the air that is pulled through the
cooling core by the fan. Depending on how much
heat is dissipated, depends on the size and design
of the core, but also on the following factors:
• Temperature difference between the air
pulled through the cooling core and the cool-
ing core itself.
• Volume of air pulled through the cooling
core, which depends on fan speed. Environ-
mental debris such as paper, straw or lint
can restrict air flow. Operating conditions
determine the necessary core cleaning fre-
quency.
• Core external insulation, which results from
(dust) particles forming an insulating deposit
on the outside of the core. The deposit im-
pedes heat transfer from the core to the air.
Operating conditions determine the neces-
sary core cleaning frequency.
• Volume of fluid passing through the core.
Generally, more fluid passes at higher en-
gine speeds when thermostats are fully open.
The flow of charge air increases when more
engine power is delivered.
• Core internal insulation, which results from
deposits inside the cooling core, which im-
pede heat transfer from the fluid to the core.
The hydraulic and transmission oil coolers
are unlikely to contain internal deposits be-
cause of the properties of oil and the oil fil-
tration system. The charge air cooler may
collect dust that has reached the core over
time due to imperfect air filtration. Nor-
mally, internal cleaning of the charge air
cooler is not required until engine overhaul.
For the location of core entry and exit ports, see
Figure 1.
0700 SRM 1595 General
1
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