Ok, I'm posting photos to illustrate. Please tell me how to do it because I don't see how can I screw a part of 1,8mm in diameter in a place where a part of 1,57mm of diameter is almost touching the fitings.
Here you can see how the fill port cover barely has room to accept a bigger diameter.
With the fill port cover removed:
The temp sensor just not fits, there isn't enough space for it:
Comparison between the fill port (1,57mm in diameter) and the temp sensor (1,8mm in diameter)
I think we are talking about different things.