Fillament comming out of wrong part of hotend (Kingroon)

Hey, it started when I tried a new filament (Maths PLA+) (back to using my same filament I always use (Overture PLA), but it didn't remove the problems)

it was badly under extruding, the extruder was both skipping & sliding, and even pushing by hand was much harder than it should be. I ended up putting a new nozzle on it, looked over everything else, and on the surface everything looks fine, but still under-extruding.
now I noticed where the rest of the filament has gone: (squeezing out above the heater block)

Attachment 17139

I noticed that bottom heater block was extremely loose, and I don't see a way of tightening it up...

any ideas?

When a new nozzle is installed, a gap of about a millimeter should remain between the heater block and the nozzle shoulder. The heat break is then threaded into the heater block until solid contact is made with the nozzle end. Snug it up securely, then turn the heater block to ABS temperatures and re-tighten the nozzle, holding the heater block from rotation. The leak you are seeing is coming from the nozzle end/heat break gap and making its way to the top of the heater block.

Thanks, I give it a go to figure it out.

slope game