SECTION 6 COOLING SYSTEM
Page 2
TD-25M EXTRA DRESSTA
Engine Cooling
An engine mounted belt driven centrifugal type pump suck the coolant thru the inlet tube (15) from
the radiator bottom manifold and pumps it through engine oil cooler cavity, engine block and
cylinder heads passages. Then, hot coolant is directed to the thermostats housing and parallel
connected coolant filter.
When the engine is cold, the thermostats are closed, which prevents circulation of low temperature
coolant through the radiator core. The coolant circulates only through the engine passages, thru
the engine bypass tube and coolant pump.
When the engine reaches operating temperature, which is determined by the thermostats, the
thermostats open the passage for coolant flow thru the tubes (6) to the upper radiator manifold.
The temperature of the coolant controls the extent of the thermostats opening, and also controls
the amount of coolant circulation. The hot coolant enters the radiator upper manifold and flows
down through tubes in the radiator core (5) where the heat is dissipated to the air being forced past
the outside of the core by the hydraulic motor driven fan.
Engine thermostats housing and radiator core is vented to auxiliary tank (3) mounted on the top of
assembly with the vent hoses (4) and (13). Auxiliary tank have fill line (14) connection to the
coolant outlet tube.
The auxiliary tank have an automotive type radiator cap with a built in pressure-vacuum relief
valve. The relief valve of the cap is incorporated to maintain a minimum and maximum pressure in
the cooling system. The valve allows excess air and vapor to escape through an overflow tube (23)
at a pressure of 45 - 55 [kPa].
Drive Train Oil Cooling System
The oil used in drive train system is directed to the inlet hose (17) of the oil cooler (2) as it leaves
the torque converter. The heat from the oil is dissipated to the air being forced past the outside of
the core tubes by the hydraulic motor driven fan. The oil is then directed to the lubrication purpose
of transmission with the hose (16).
Fuel Cooling System
The engine uses high pressure injection system increasing fuel temperature. Inline connected fuel
cooler (10) is mounted to the drain line to maintain fuel temperature below 71 [°C]. The heat from
the fuel is dissipated to the air being forced past the outside of the core tubes by the hydraulic
motor driven fan. The fuel is then directed to the fuel tank with the hose (11).
Hydraulic Motor Fan Drive Oil Cooling System
Torque converter mounted and driven hydraulic oil pump is pumping oil to the fan drive hydraulic
motor, then oil is directed to the oil cooler (7) thru the hose (9). The heat from the oil is dissipated
to the air being forced past the outside of the core tubes by the hydraulic motor driven fan. The oil
is then directed to the hydraulic oil tank thru the hose (8).
Hydraulic motor speed is controlled by the three sensors located in the engine intake air system,
engine cooling system and drive train system.
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