No flow over new thermostat valve

[fijn]

Hi all forum members,

I have an issue with my new thermostat valve Colorstat. I replaced my old thermostat with this new one and now I do not have flow over the thermostat and it does not het hotter than 50degree Celsius (122 Fahrenheit). I have bleed the system and also installed the extra vent in the hose on top of the engine. I am pretty sure I have completely bleed the system (done it several times) but I get no flow over the new thermostat. Just to check I have placed back the old one and that works. Only the old one doesn't close completely the radiator exit. So there is flow with the old one but no flow with the new one.

Does anyone have maybe a suggestion?

Many thanks Jaap