asturcon said..
Everything can happen, I have 4 Severneboards and I have changed the valve in the two oldest. I had to smash one valve as I could not get it out, and I obesrved that there were no rubber-ring between the hole and the valve. may be the same for you? The valves had no inscriptions. I changed them to the best valves from "GORE" and with the inscriptions:
M12 X 1,5 PMF 100585
Its the best high flow valve from Gore. Do not forget to put a thin layer of silikon before screwing in the valve.
New PolyVent High Airflow Brings Next-Generation Performance to GORE? Protective Vents Screw-In Series | Gore
John
Thanks
i ended up getting an m12x1.5 alloy plug screw with o ring from automotive shop. Use it as a vent screw
seems to work ok so far