Engine System - Operation
–UN–27SEP04
Cooling System
CD30684A
105 4
A—Water pump B—Thermostat C—Coolant temperature sender
D—Coolant recovery tank (when equipped)
The principal components of the pressure cooling system are the radiator, water pump, multi-blade fan and thermostats. During the warm-up period, thermostat (B) remains closed and coolant is directed through a by-pass to suction side of water pump (A). The coolant then circulates through the cylinder block and water pump only to provide a uniform and fast warm-up period.
E—Radiator cap F—Radiator
G—Lower radiator hose H—Engine oil cooler
Here it circulates through the block and around the cylinder liners. From the cylinder block, coolant is then directed through the cylinder head and into thermostat housing. With the thermostat open, coolant passes through the housing and upper radiator hose into top of radiator (F) where it is circulated to dissipate heat. On some engines the water pump has two further hose connectors which lead to the engine oil cooler (H).
Once the engine has reached operating temperature, the thermostats open and coolant is pumped from bottom of radiator via bottom hose into the cylinder block.
CD,CTM125,211 –19–09SEP04–1/1
CTM125 (22MAR06)
105-4
POWERTECH 2.9 L Diesel Engines 032306
PN=228