Sorry, I wrote it a bit wrong. During cooking, the thermostat opens smoothly and I did not even boil water until it was completely opened. I remember I changed it for a new about one year ago. There is only "Made in England" written on it and a "82" or "88" stamp (I do not remember).
Could you tell me how to use the "bleed screw"? When the engine is hot or cold? When engine is running or turned off?
Thanks.