I'm still fairly new to 3D printing; got my Ender 3 V2 for Christmas last year. Recently the tension arm in the stock extruder snapped, so I bought and installed an all-aluminum replacement. My first successful(ish) print since installing it lasted two to three hours before I noticed the filament wasn't feeding. It had softened and clogged the lead-in to the Bowden tube just past the tooth gear. I figure the problem comes from (and what probably broke the original plastic) heat buildup; the new aluminum frame was VERY hot to the touch. I also noticed that the extruder motor was rather hot as well.
So you all know where I am: all I've printed with is PLA at 195 °C. Since changing extruders, I was getting over extrusion and dropped it to 185 °C and increased the retraction from 5 mm to 6.5 mm. The new one doesn't have (easily) adjustable tension, but the tension felt as strong as I had it on my old one, so I left it alone. I currently print within an enclosure, one of Creality's foil-lined ones since my printer is located in the garage (this is more for dust, but for longer prints I felt it was good to have since at the time it was getting very cold at night in the garage).
I don't think it's heat creep, since that meant it went all the way up the Bowden tube. My first guess is the ambient heat inside the enclosure. I am currently trying a new print with the top and side openings folded up to allow airflow. But I welcome more experienced suggestions and input.
I think I was getting away with the low temperature (185 °C) because my printing enclosure held heat so well. I'm attempting to print outside the enclosure today to start removing variables to my problem, if it under-extrudes, I'll bump the temperature up again.
Please note that I replaced just the frame.
I wouldn't know how to adjust the voltage [of the Z-stepper] if indeed the [pre-set factory calibration is incorrect and causing the stepper to heat up]. The new tension arm is a bit tighter than I had it set on my old, but I can't imagine it's making enough resistance to overwork the motor without seeing other issues first.
I didn't see any signs of Heat Creep when I pulled out the filament. The only softening I saw was in the direct drive; it had been pushed into a conical shape that plugged the port into the Bowden just past the gears. I'm still leaning towards an issue with the direct drive (is that what it's called? still learning the terms). the aluminum was too hot to touch and I had to wait 10 minutes before I could safely depress the tensioner and pull the filament out. That or the motor is overheating trying to pull Filament through.
The motor driving the filament is on the opposite side of the Teflon tube, mounted to the vertical frame - it is not on the nozzle side of the Teflon tube.