TYM T303HST, Workshop Manual

Page: 53 / 249

Chapter 3.Engine accessories
SECTION 1. RADIATOR
1.General description
The pressure cooling system includes mainly the
radiator,water pump,multi-blade fan, and
the thermostat.During the warm-up period,the
thermostat remains closed and coolant is directed
through by-pass to the suction side of the water
pump.
Coolant then circulates through the cylinder block
and water pump only to provide a uniform and fast
warm-up period. Once the engine has reached
operating temperature,the thermostat opens and
coolant is pumped from the bottom of the radiator
via the lower hose into the cylinder block. Here it
circulates through the block and around the
cylinders.
From the cylinder block,coolant is directed through
the cylinder head and into the thermostat
housing.With the thermostat open,coolant passes
through the housing and upper radiator hose into
FIG.3-1
through the housing and upper radiator hose into
the top of the radiator where it is circulated to
dissipate heat.
FIG.3-2
3-1