Page 133 - CTS - Mechanic Diesel - TP

MECHANIC DIESEL - CITS

EXERCISE 7.4: Testing the Thermostat valve

Objectives
At the end of this exercise you shall be able to
• remove the thermostat valve
• inspect and test the thermostat valve
• refit and test the thermostat valve.

Requirements

Tools/Instruments Materials
• Trainee’s tool kit - 1 No. • Cotton cloth - as reqd.
• Water jar - 1 No. • Kerosene - as reqd.
• Thermometer - 1 No. • Soap oil - as reqd.
• Heater • Coolant - as reqd.
Equipments/Machines • Gasket - as reqd.
• Thermostat valve - 1 No.
• Work bench - 1 No.

Procedure

Inspection (Thermostat valve)
1 Remove the thermostat cover from the thermostat case. Fig 1
2 Remove the thermostat valve.

3 Clean the thermostat valve cap, and valve seat.
4 Tie the thermostat valve’s collar with a thread.
5 Immerse the thermostat valve in water. Ensure that the
thermostat valve (1) is fully merged in the water but does
not touch the walls or the base of the jar.
6 Heat up the water (Fig 1).
7 Note down the temperature of the water in the
thermometer (2) at which the thermostat starts to open.
8 Note down the temperature at which the thermostat
opens fully.

Fig 2

9 Remove the thermostat valve (1) from the water and
measure the gap between the thermostat collar (2) and
the shroud (3). (Fig 2)
10 Compare the thermostat’s opening temperature,
thermostat’s opening (4) and the temperature at which
the thermostat opens completely, with the specifications
given by the manufacturer. If any of these three
observations do not match with the manufacturers
specifications, then replace the thermostat (Fig 2).

11 Fit the thermostat in the thermostat case.
12 Fit the thermostat cover in the thermostat case.

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