CHAPTER 12
COOLING GROUP REPAIR INSTRUCTIONS
12-1. General.
a. The cooling group consists of the radiator
grille, shutter assembly and the shutter thermostat.
b. The radiator is mounted at the front end of the
engine generator set just behind the grille and shutter
assembly. It is equipped with inlet and outlet hose
connections, a filler cap and an overflow tube. A
drain valve is located on the lower right side of the
radiator. A shroud and fan guard are mounted on
each side behind the radiator, enclosing the fan.
c.
The radiator shutter is mounted on the front
of the radiator. The shutter control is mounted on
the lower right side of the radiator and operates by
thermal expansion.
A plunger inside the thermostat,
which is affected by temperature in the radiator,
actuates the linkage system to the shutter. The
shutter will remain closed until the engine warms up,
at which time it will open upon action of the shutter
control.
A control lever is provided for manual
operation of the shutter control in case of thermostat
failure.
d. The fan is located behind the radiator on the
front of the engine.
Driven by belts when the engine
is running the fan draws cooling air through the doors
at the rear of the unit and exhausts it through the
radiator core, shutter and grille.
12-2. Radiator Assembly Removal.
A malfunction of the radiator, shutter assembly or
thermostat is usually indicated by an abnormally high
reading on the coolant temperature gauge located on
the engine control panel.
To isolate the cause pro-
ceed as follows:
a. If the shutter assembly is closed, operate the
manual control and open it. If the temperature begins
to drop toward normal, the probable cause is a faulty
shutter thermostat. (Refer to the Operator and
Organizational Maintenance Manual).
b. Open the radiator fill cap and check for a suff-
cient amount of coolant. Add coolant if necessary and
observe temperature gauge for a drop in temperature.
C. Shut the engine down. Examine the pulley
belts for tension. If they are tight examine the
fan for bent or broken blades and freedom of
motion.
d. When it is determined that there has been a
failure of the radiator, fan, or shutter assembly,
remove the radiator, grille, shutter assembly,
shroud and fan guard. (Refer to the Operator and
Organizational Maintainance Manual).
12-3. Radiator and Shutter Repair and Test.
a. Clean all parts with cleaning solvent Federal
specification P-D-680 and dry thoroughly with
compressed air at 10 to 15 pounds pressure.
b. Inspect all hardware and threaded areas for
damaged or crossed threads.
c. Inspect shutter control body for damage and
proper operation.
d. Repair control assembly and shutter assembly
by Emplacement of defective parts. (See figures 12-1
and 12-2).
e.
Using compressed air, remove all dirt and
foreign material from the radiator core.
(1) Solder or braze any radiator core leaks.
(2) Straighten bent cooling fins.
f. Replace all worn, damaged, or defective parts.
g. Test the radiator for leaks by placing the
radiator with outlet connection sealed in a tank of
water.
Apply compressed air of 10 to 15 psi at
filler opening and observe for leakage indicated by
air bubbles in the water.
12-4. Radiator Assembly Installation.
Install the fan guard, shroud, radiator, shutter as-
sembly, grille and shutter thermostat. (Refer to the
Operator and Organizational Maintenance Manual. )
12-1
