ARMY TM 9-6115-464-34
AIR FORCE TO 35C2-3-445-2
NAVY NAVFAC P-8-624-34
Section Ill. MAINTENANCE OF ENGINE COOLING SYSTEM
The engine cooling system is a circulating pressure type system. It consists of a radiator, a belt driven
cooling fan and centrifugal water pump, a coolant control thermostat, a thermostatically controlled shutter
assembly, and a protective grille. The water pump receives coolant from the lower radiator hose and circulates
it through the engine cylinder block and cylinder head. As it circulates through the engine, the coolant absorbs
heat generated by engine operation. When the engine reaches normal operating temperature, the coolant
control thermostat opens and the coolant returns to the radiator through the upper radiator hose. As the heated
coolant circulates through the radiator, the cooling fan blows air through the radiator air passages which
dissipates the heat. The shutter assembly blocks the flow of cooling air until the coolant in the radiator reaches
normal engine operating temperature.
Refer to the Operator and Unit Maintenance Manual for grille maintenance instructions.
3-28. SHUTTER CONTROL ASSEMBLY.
a. Removal. Refer to the Operator and Unit Maintenance Manual for shutter control assembly removal
(1) Remove screws (1, figure 3-26) and Iockwashers (2) to remove housing (3), gasket (4), thermostat
(5), nut (6) and piston (7). Discard gasket.
(2) Remove and discard packing (8).
(3) Remove retaining rings (9) and loosen setscrews (10) to remove shaft assembly (11). Do not
disassemble setscrews (12), cam (13) and shaft (14) unless inspection reveals damage.
(4) Remove bushings (15).
(5) Remove retaining rings (16) to remove shaft (17), lever (18) and bushings (19).
(6) Remove retaining ring (20) to remove actuator pin (21) with assembled parts.
(7) Remove retainer (22), spring (23) and washers (24, 25, and 26) from actuator pin.
(8) Remove nut (27), spring (28), screw (29), and flat washer (30) to remove manual control arm (31)
from flange (32).
c. Cleaning,. lnspect, and Repair.
Solvent, Dry Cleaning P-D-680, Type II is flammable and moderately toxic to skin,
eyes and respiratory tract. Eye and skin protection required. Good general ventilation
is normally adequate. Failure to observe this warning could result in severe personal
(1) Clean all parts with dry cleaning solvent (Federal Specification P-D-680) and dry thoroughly.
(2) Visually inspect housing and flange for cracks, breaks, corrosion, and other damage.
(3) Inspect shafts and pin for scores, deep water patterns and other damage.
(4) Inspect manual control arm for cracks, corrosion and excessive wear.
(5) Check springs for cracks, corrosion, breaks, chaffing and distortion.
(6) Inspect lever for cracks, corrosion, and excessive wear.