Filament leaking and clogging (not on nozzle)

Hi. I've built a Prusa i2 and I'm having some issues with my hot end, which is based on the E3D v5.



At first I could extrude and print without major problems, although there was filament leaking to the small hole where the thermistor goes (see figure, the 1.5mm diameter hole). Then it began clogging. The extruder would pull the filament down and it would get all twisted before entering the heat sink and the PTFE tube because it couldn't pull down one piece of filament that was already stuck down there.

The nozzle temperature is 230C.

I'm not using a fan attached to the heat sink, maybe it's something related to that?

Any help is appreciated.

Thanks,

Gustavo.

With an E3D style hotend, a cooling fan on the heatsink is required. Without a fan, it WILL jam.