How to test engine thermostat?

[platofan]

I have just bought a new one and have read you can test to see if it opens in boiling water.

All I can see when I put it in the measuring jug of hot water is bubbles, wheras when it goes into a cold jug of water I get no bubbles.

Not really sure as to what I should be looking for. Any ideas?

Thanks

 

[willives]

There is normally a rubber diaphragm which is connected to a coil/spring. When the water temp is hot it causes the coil to expand/contract and open the diaphragm and allows water to pass. When it cools it closes up and stops the water flow.

The last thermostat I tested, the diaphragm moved around 10mm.

 

[platofan]

Thanks for that. I'll test it again.