question Zetor 7245 : thermostat not engaging

[lapioche]

I replaced the thermostat housing and water pump. After the replacement, the upper pipe got really hot without the thermostat opening even after prolonged period. I ended up removing the thermostat and letting the coolant flow continuously into the radiator. This is summer so it seems OK, but I don't think this is normal. The thermostat is marked 78C. Any thought on what might be the problem?

 

[Joachim]

It is best to only install original Zetor or original Wahler thermostats. These start to open at 78 - 80°C and should ensure an operating temperature of 85 to 98°C.

Throw the thermostat into a pot of water. Bring the water to a boil slowly and measure the water temperature every now and then.

Then let the water cool down and see if it closes again.

This is how you can test it.

When installing the thermostat, it is important to install it so that the small vent hole is facing upwards. Otherwise there may be an air pocket and the thermostat will not open.

Maybe a stupid question - but did you install the thermostat the right way round? And did you also put the housing in the right way round?

Photos???

 

[lapioche]

The thermostat is original. I got it from a Zetor shop. I'll test it then retry installing it with your comments in mind. Thank you!