TIAGO

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1.2L REVOTRON ENGINE
84
 Components :
1. Radiator & Fan Shroud Assy :
The radiator is a heat exchanger that is used to
dissipate the coolant heat. A radiator fan is used
to create forced air circulation.
Radiator consists of radiator core, inlet tank and
outlet tank.
Cores are usually made of aluminum. The core
has two sets of passages, a set of tubes and a set
of fins attached to the tubes. The tubes run from
inlet tank to outlet tank. Coolant flows through the
tubes and air flows between the fins. The
atmospheric air passing between the fins carries
away the heat, which lowers the temperature of
the coolant.
2. Auxiliary Tank :
The radiator cap controls the system pressure to
1.4 kg/cm2. Once the pressure exceeds 1.4
kg/cm2 the cap lifts off the seat and the coolant is
allowed to escape into a auxiliary tank.
As the engine cools down the system pressure
falls down and vacuum is formed. The auxiliary
tank allows the water from the tank to go back
into the radiator. Thus the system does not have
any coolant loss during normal operation.
3. Thermostat :
The thermostat controls the flow of coolant as
follows.
a) During a cold start, thermostat does not allow
coolant to flow to radiator since it is closed;
instead the coolant flows through thermostat
bypass outlet back to the engine. Thus short
circuiting of radiator which helps in attaining
engine working temperature in a very short
period.
b) As soon as the coolant temperature reaches
the opening temperature of the thermostat, the
thermostat valve starts opening gradually and
coolant starts flowing to the radiator. At the
same time the thermostat by-pass starts
closing gradually.
c) As the engine working temperature reaches
thermostat full open temperature, the
thermostat valve opens fully and thermostat
by-pass valve closes completely. In this
condition maximum quantity of engine coolant
flows from radiator to water pump.
Testing Parameters:
 Thermostat start open temperature is 88 0±20C
at 0.1 mm travel.
 Full open temperature is 102 0C at 8mm (Min.)
travel.
 Leakage through main valve (including jigle
pin) at room temperature and 0.2kg/cm2 is
300cc 2/min