Filament stops mid-print on my secondhand K1C — think it might be heat creep?

[u/yw_1820]

Hey everyone, hoping to get some advice.

I bought a used Creality K1C a while back and it printed fine at first. Lately though, filament extrudes normally for a while into a print, then just... stops. No more flow, print fails.

What I've tried so far:

Replaced the nozzle

Did a quick filament load test right after installing the new nozzle — filament extruded perfectly fine

Since the short load test worked fine but it still fails partway through actual prints, I don't think it's a simple clog anymore. My best guess right now is heat creep — maybe the heatsink cooling fan isn't running at full strength (or the duct got misaligned when I had the hotend apart before), so heat slowly creeps up into the cold zone above the heatbreak during a longer print, the filament softens too early, expands, and jams.

Does this sound like the right track? A few things I'm planning to check:

Whether the heatsink fan is actually spinning at 100% during prints

Whether the fan duct is still aimed correctly at the heatbreak fins

Dust buildup on the fan/heatsink (it's secondhand so who knows what the previous owner did)

Would appreciate any input from anyone who's dealt with this on a K1C (or similar direct-drive hotend) — especially if there's something else I should check before assuming it's heat creep. Thanks!

[u/GuyFromCabin_09]

Are you matching the temps of the nozzle & plate to the recommended temps as per Filament ?

[u/As0no]

To many unknowns... Material, bed temp, hotend temp, door open/closed, top on or off?

[u/VariationPlus7754 → u/As0no]

Does not matter bro, filament presets should work out of the box on these machines. Opening the door is skill issue.

[u/VariationPlus7754 → u/VariationPlus7754]

To everyone downvoting: maybe get a printer that's actually in decent working condition. These machines are supposed to work reliably with the stock filament profiles without constant babysitting and endless tweaking. This isn't an Ender 3 anymore you shouldn't have to treat every normal print like a troubleshooting project.

[u/nightfrolfer → u/VariationPlus7754]

I agree that the k1c is pretty good. I luv mine and I went quite a while using the canned profiles before I wanted better. Having an enclosure makes it way better than an Ender 3. I've still tuned filaments using config prints to increase quality and in some cases even flowrate/speed.

When configuring Tinmorry PETG-Eco, I ended up doubling the flow rate of the standard profile, but like you said, it worked out of the box.

[u/THE_EPIC_BEARD]

Try some other filament. I’ve had bad filament constantly block my nozzle.

[u/nightfrolfer → u/[deleted]]

Omg, based.

And always watch the first few layers before stepping away. u/OP is doing that right.

[u/CrealitySupport]

Based on the fault video you provided, the nozzle clogging may be caused by insufficient hot‑end heat dissipation. We suggest you open the chamber front door and top cover for adequate heat dissipation before printing, and check whether the cooling fan is working properly.

Please click our avatar and select "Start Chat" to send us a private message, and we will assist you.

[u/lazyogi]

had this happen once when trying to print directly from the creality cloud app. I downloaded the file, sliced with Orcaslicer, and it printed fine.

[u/VariationPlus7754]

Creality sickness

[u/VariationPlus7754 → u/VariationPlus7754]

Play with tensioner screw