Radiator Cap - Kubota EA330-E4 Series Workshop Manual

EA330-E4, WSM

[3] RADIATOR CAP

Radiator Cap Function
 When Radiator Pressure is High
When temperature increases inside the radiator,
there is expansion of water followed by conversion of
water to steam as the temperature continues to
increase.
The pressure valve is designed to prevent internal
pressure rising above specified opening pressure
(110 kPa, 1.1 kgf/cm
radiator, therefore, the pressure valve opens allowing
steam to escape, as shown in the figure.
An additional function of the radiator cap is to
prevent foam forming inside the engine and to restrict the
loss of coolant resulting from temperature increase.
 When Radiator Pressure is Negative
When the temperature of the coolant decreases,
internal pressure becomes negative as a result of water
contraction. In this situation, the vacuum valve opens
allowing the entry of air and a return to atmospheric
pressure, thereby preventing distortion of the radiator.
(1) Pressure Valve
(2) Vacuum Valve
1-M14
ENGINE
2
, 16 psi) in order to protect the
[A] At High Pressure
[B] At Negative Pressure
9Y1211018ENM0024US0
KiSC issued 05, 2015 A