Well I did sort it kind of
Both new thermostats didn't have the bleed nipple (I gues it is the part on the outer ring of thermostat sticking out.
I didn't have the original O-ring, someone before probably replaced the ring or thermostat, but the ring placed was quite wider than the thermostat and was glued to the housing somehow. I bought the car 6 months ago and it was loosing coolant but barely so this seemed to hold it.
I used the gasket that puls on the thermostat instead of O-ring, cause I don't have it, the one with the thermostat doesn't work. I also put some high temp sealant around that gasket ant thermostat and then screwed everything by hand as tightened only lightly with the key. Let it dry for 3 hours then tried it.
Got it to temp with collant tank opened and pressed the coolant tubes and refilled it
Everything is dry so far not a single drop anywhere after 20 miles.
I did order an oem O-ring from volvo but this won't arrive before next Friday.
I guess I will have to source also a new housing or atleast a cover of the housing in the future