TM-5-3805-254-14-P-2
TRUCK, DUMP, 20 TON, 6X4, ON-OFF HIGHWAY 71,000 GVW, IHC MODEL F-5070 (CCE)
TECHNICAL MANUAL; OPERATOR’S, ORGANIZATIONAL, DIRECT SUPPORT, GENERAL SUPPORT AND DEPT MAINTENANCE MANUAL (INCLUDING REPAIR PARTS INFORMATION AND SUPPLEMENTAL MAINTENANCE INSTRUCTIONS)
JUNE 1980
TM-5-3805-254-14-P-2 - Page 243 of 894
MOTOR TRUCK SERVICE MANUAL
COOLING SYSTEM
GENERAL
COOLING SYSTEM
PREFACE
Because the effects or damage that result from an
improperly maintained cooling system usually occur
gradually, this system is often times neglected.
However, the cooling system must be treated with the
same attention to maintenance as is given such other
systems as fuel, ignition and lubrication.
A review of the
cooling system’s function will show this more clearly.
In general the circulation of water through the cooling
system relies entirely upon the water pump.
The water
pump draws water from the radiator and force s it
through the water jackets and cylinder head.
There it
accumulates heat.
Then the water flows to the upper
radiator tank and down through the radiator core, being
cooled by air from the fan.
This process of removing
heat from water as it circulates holds the engine to its
most efficient operating temperature.
The following paragraphs point out several facts
about cooling system components, The affects of cooling
system neglects and procedures to be followed for
cooling system maintenance.
Trouble Shooting helps
have also been prepared.
COOLING SYSTEM COMPONENTS
Radiator
This component which is one of the most important
in the cooling system is made up of the following parts:
1. Top and bottom tank look for leaks, particularly
where tank is soldered to core.
Vibration and
pulsation from pressure can fatigue soldered
seams.
2. Filler neck the sealing seat must be smooth and
clean.
Cams on filler neck must not be bent or
worn so as to allow loose fitting cap.
Make sure
overflow tube is not plugged.
3. Radiator cap is the pressure sealing type.
Its
purpose is to hold the cooling system under a
slight pre s sure, increasing the boiling point of
the cooling solution and preventing loss of
solution due to evaporation and overflow.
The cap (Fig. 1) has a spring-loaded valve, the seat
of which is below the overflow pipe in
the filler neck.
This prevents the escape of air or liquid
while the cap is in position.
When the cooling system
pressure reaches a predetermined point, the cap valve
opens and will again close when the pressure drops
below the predetermined point.
Fig. 1
Radiator Cap (Pressure Type)
When removing the pressure type cap from the
radiator, perform the operation in two steps.
Loosening
the cap to its first notch raises the valve from the gasket
and releases the pressure through the overflow pipe.
In
the first stage position of the cap it should be possible to
depress the cap approximately 1/8".
The prongs on the
cap can be bent to adjust this condition.
Care must be
taken that the cap is not too loose as this would prevent
proper sealing.
CAUTION:
When removing the cap, loosen it slowly
and then pause a moment.
This will avoid possible
burning by hot water or steam.
Continue to turn the cap
to the left until you can remove it.
4. Tubes because the se are very small they can
become easily clogged, or partially so, by rust
and scale.
The general condition of cooling
system
and
operating
temperature
are
indications as to whether or not tube s are clean.
Another good test is to feel core for cold spots.
5. Fins these thin metal sheets radiate or pass off
heat picked up by tubes.
They should be kept
free of bugs, leaves, straw, etcetera so as to
allow the free passage of air.
Bent fins should
be straightened.
239
Back to Top
