TM 5-3805-280-24-2
Engine System Operation and Tests
105
A--Water Pump
H--Passages
M--To Radiator Top Tank
9
B--Coolant Passage
I--Thermostat(s)
N--Drain Valve
Adapter
J--Water
O--Suction Side of Water
C--Oil Cooler Drain Plug
Manifold/Thermostat
Pump
D--Oil Cooler Plates
Housing
P--High Temperature
E--Main Coolant Gallery
K--Dual Thermostat
Coolant
F--Coolant Jacket
Assembly
Q--Low Temperature
G--Block Deck Passages
L--Bypass Circuit
Coolant
During the warm-up period, thermostat(s) (I) are closed
The cooling system includes the radiator, water pump
and coolant is directed through a bypass circuit (L) into
(A), and thermostat(s) (H).
suction side of water pump. The coolant continues
circulating through the cylinder block, cylinder head,
Coolant is circulated from the water pump into the
and water pump to provide a uniform and fast warm-up
coolant passage adapter (B) and circulates around the
period.
oil cooler plates (D). From the oil cooler, coolant flows
into the main coolant gallery (E). From the gallery
Once the engine has reached operating temperature,
coolant flows into the coolant jacket (F), around the
the thermostat(s) open and allow coolant to flow
cylinder liners, up through the block deck passages
through the upper radiator hose to the radiator top tank
(G), and into the cylinder head. In the cylinder head,
(M). Coolant circulates through the radiator, dissipates
the coolant flows through passages (H) around the
heat, and then flows out of the radiator through the
intake and exhaust ports, valve seats, and injection
lower hose and into the suction side (O) of the water
nozzles. Coolant flows toward the front end of the
pump. Coolant continues flowing through the engine
cylinder head and exits through the water
and radiator circuit until the coolant temperature drops
manifold/thermostat housing (J). Engines may be
below the thermostat opening temperature.
equipped with a dual thermostat assembly (K).
RG,105,JW7659 1921NOV972/2
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