Quote Originally Posted by Iain View Post
My flashforge I purchased in Feb has the new extruders. They are very easy to disassemble and clean, on only one occasion with ABS filament it would not retract or extrude and had to push it out manually. I think I had left it in the extruder for a long period of time without using it.
Yep, it does happen unfortunately. Some filaments I can leave in there forever, some bulb up and wont unload.

The other extruder is always hot even if it's not getting used, and while 40-50c isnt enough to melt the plastic in the dormant nozzle, it is enough to make it swell. If the thermistor is reading 45c, the inside of the tubing would be around 5c hotter. Have you left anything in your Car before and it melted over time? car's get to 50c easily inside, so you can see how the filament gets affected by small residual heat over time.