WATER PUMP -624880028

TM 5-2420-222-20-1

COOLING SYSTEM - CONTINUED

WATER PUMP

Centrifugal-type pump driven by V-belt from crankshaft pulley.

Circulates coolant through cooling system.

LUBRICATING COOLER-TO-WATER PUMP COOLANT LINES (2)

Route coolant from water pump to lubricating cooler, and back to water pump.

LUBRICATING COOLER (ENGINE OIL COOLER)

Considered part of engine lubrication system.

Coolant passes through core, cooling engine lubricating oil.

ENGINE BLOCK COOLANT PASSAGES

Cavities cast in engine block carry coolant around block components to cool them.

Route coolant from water pump to cylinder head coolant passages.

ENGINE BLOCK DRAINCOCK

Allows draining of engine block coolant passages on loader backhoes without optional engine coolant heater.

CYLINDER HEAD COOLANT PASSAGES

Cavities cast in cylinder head carry coolant around head components to cool them.

Route coolant from engine block coolant passages to thermostat housing.

ENGINE WATER TEMP. GAGE

Senses engine coolant temperature at cylinder head and transmits this information through capillary tube to

instrument panel gage for readout.

THERMOSTAT HOUSING AND THERMOSTAT

Thermostat housing mounted to upper-left front of cylinder head.

Spring loaded bellows-type thermostat remains closed, routing coolant through bypass hose directly back to water

pump until coolant coming from cylinder head reaches minimum operating temperature. When this temperature is

reached, thermostat begins to open, routing some or all coolant through radiator inlet hose to radiator for cooling.

Shorten engine warmup time and maintain minimum operating temperature.

RADIATOR INLET HOSE

Routes coolant from thermostat housing cover to top tank of radiator.

RADIATOR BYPASS HOSE

Routes coolant from thermostat housing directly to water pump for re-circulation without passing through radiator

until thermostat opens.

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