How?

It's worth noting that some but not all combinations of heat break, nozzle, and heater block require re-tightening at the temperature used for printing. Basically, different metals expand different amounts when they're heated, so if the block expands more than the other two, a gap will open up between them, and melted filament can find its way through.

Hey I've been there. Take it apart carefully and inspect it as you go. Do lots of reading, clean it up, put it back together and hopefully it won't happen again - but know that it might if you don't find a cause. Sometimes things have to get worse before a cause becomes obvious.

I've got a Prusa, but I've had to replace many different parts on it, sometimes multiple times. Some of that was factory issues. Some of that was my fault. Some of it was just bad luck.

I still love the hobby, but it sure as Hell isn't trouble free.

Okay, using a microswiss hot end for an example, and that's a clean photo. They're all usually about the same anyhow. What's going on here is a very common mistake to make. the immediate cause is that the heat break (red arrow in the picture) is not screwed on to the heater block tightly enough, and some filament is oozing out the top rather than getting forced out the nozzle.

The solution is to heat it up, clean everything up with a brass brush or something similar. Then remove the nozzle and run filament through while it's hot, clearing out any gunk that's built up.

Now, to get it on there tight enough, what you need to do is heat up the nozzle to higher than you normally print at, then tighten it down as tight as it can go while trying very hard to not burn yourself.

You can get the same problem with the nozzle oozing, out (blue arrow) as well, so while you're running hot, go ahead and put the nozzle back in and get it as tight as you can, too. once it's done, you can loosen the set screw above the heat break (green arrow. the set screw holds the heat break in place.) and turn the block so it's more or less aligned with the printer. Let it cool back down and bring it up to temperature and check for leaks again.

and just for the record. everyone here has probably had this happen. I just want to make that clear. please don't give up. You'll reach a point where it all makes sense. If you need to step away for a bit, that's okay, but also, don't be afraid to come back to it.

The problem is I don’t even know what happened or how the pla got around that silicon sleeve.

It's kinda normal. If the hotend clogs there's only two places for the plastic to go (or it can stop going into the hotend), the other one is up. And this is both more common and way better than up.

It doesn't look like it, but the printer pushes the filament with a lot of force. It's normal for it to just go into some completely unexpected direction that you can't replicate by hand.

Anyway, if it's working correctly and what bothers you is the extra plastic, just heat the printer until some 160 °C and pull it away.

Maybe its best to put it away for some time and then come back to it when you feel its time. I mean, its a hoby and it can be frustrating, but its worth IMO. Dont forget its a machine and not a plug-and-play device.

Im in this hoby for 10ish years and I never had a leak. Probbly because I was reading about that even before I got my first printer. I did have many other issues and failures, but they almost never happen anymore. Most of the crap stopped after I got Ultimaker 2, but I believe experience is the main reason.

Like others said, your nozzle wasnt sealed (tightened) against the heat brake properly. You have to heat up your hotend before tightening, but dont use full strength or you might break your nozzle.

Now you can clean it up or just replace heatbrake and nozzle, at least parts are available everywhere

Thanks for explaining!

Also, IMO the “why isn’t this working, why did I do this” stage is a right of passage and sign of progress in any new activity! Keep on trucking!

True! but it's still very painful! hahaha

Balls. Of steel.