UM2+ Trouble after replacing nozzle

[Daviren 2]

I realized that I had never changed the nozzle on my machine since installing the Olsson block (😬) so I ordered a few .4mm nozzles from Matterhackers. After installing the nozzle, though, I haven't been able to get the machine to extrude properly. I just did a big overhaul, replacing the feeder and Bowden tube, taking apart the head and cleaning the whole line. I've tried a couple of different nozzles, but no luck.

 

After the latest attempt, though, I realized that there's plastic leaking on the outside of the nozzle through the Olsson block. What am I doing wrong? Why can't I seem to install these nozzles correctly?

 

[Daviren 2]

Okay, I think maybe I solved this. When I heated the nozzle all the way up to 210C, I found that I was able to tighten it a few more times with minimal force. For whatever reason, tightening it at 100C didn't give me the same effect.