Last updated: October 20, 2026

How to fix a clogged 3D printer nozzle

Your print starts thin and patchy, the extruder clicks, or nothing comes out at all. It's often a clogged nozzle, and most clogs clear in a few minutes without taking anything apart. Work down this list in order and stop as soon as plastic flows smoothly again.

Is it really a clog?

Plenty of "clogs" are something else. Signs it really is the nozzle:

• Lines get thinner, gappy or stop part-way through a print (called under-extrusion, which has other causes too)
• The extruder makes a clicking or knocking sound as its gears slip on the filament
• When you load filament, it curls sideways out of the tip instead of dropping straight down, or nothing comes out

Before you heat anything, rule out the easy stuff:

• The spool: is it tangled, empty, or catching on the holder? A spool that can't turn freely starves the printer.
• The path: is the tube or guide kinked, or has the filament snapped inside it?
• The first layer: if the problem is only on the first layer, the nozzle may simply be too close to the bed. See how to level a 3D printer bed.

Bambu Lab suggests a neat test for its A1 printers: take the hotend out and try extruding without it. If filament comes out smoothly without the hotend, the clog is in the hotend. The same logic works on most printers: find the last point where filament still moves freely.

Step 1: Heat it up and push filament through

Heat the nozzle a bit hotter than you normally print, wait a minute or two so the old plastic fully melts, then load filament or gently push it in by hand. Prusa's clogged-nozzle guide, for example, uses 260 °C if you were printing PLA and 280 °C after PETG or ASA, waits two minutes, then pushes new PLA through. Bambu Lab's A1 guide uses about 250 °C to manually extrude.

If plastic starts flowing in a straight, even strand, push through a bit more, then run a small test print. Many clogs end right here.

Step 2: Do a cold pull (for partial clogs)

If some plastic comes out but it's thin or curly, a cold pull is the best next step. You fill the nozzle with PLA, let it cool until it's soft but not runny, and pull it out. The end that comes out is a little mold of the inside of your nozzle, with the dirt and burnt bits stuck to it.

The basic method, based on Prusa's cold pull guides (check yours, because how you reach the filament differs by printer):

1. Use plain PLA. Prusa found it works best because it keeps its shape; a different color from what was loaded makes it easy to see when the nozzle is clean. Cleaning filament also works.
2. Heat the nozzle to about 270 °C and push the PLA in by hand until it pours out of the tip.
3. Turn the heat off. Keep pushing as it cools, until plastic stops coming out (around 170 °C). The nozzle has to stay full.
4. Let it cool further. Prusa's guides pull at about 85 to 100 °C depending on the model.
5. Grab the filament with pliers and pull slowly, steadily and straight up, not sideways, while holding the print head with your other hand.
6. Look at the tip. If you see dark specks or old color, repeat. Two or three pulls in a row is normal.

Bambu Lab's A1 method is a little different (it heats to 220 °C and pulls at about 100 °C), and some newer printers, like Prusa's MK4 on recent firmware, can run a cold pull for you from the menu. If your printer has its own procedure, use it.

Step 3: Clear the tip with a needle (0.4 mm nozzles and up)

Many printers ship with a thin unclogging pin. With the nozzle heated to a little above the temperature the stuck filament needs, gently push the pin up into the tip and move it up and down a few times, then extrude again. Repeat a couple of times if needed.

• Bambu Lab notes this doesn't work on nozzles smaller than 0.4 mm.
• Wear gloves and keep your face clear: Bambu warns that pressure built up behind a clog can make hot plastic spray out suddenly.
• Never force it, and don't use random wire or drill bits that could scratch or widen the hole.

Step 4: Know when to replace it

If none of this gets plastic flowing, the blockage is probably higher up inside the hotend. Prusa's guide says that if a hot push doesn't restore flow, the nozzle most likely needs replacing. On many beginner printers, like the Bambu A1 series, you swap the whole hotend in a minute or two; on others you unscrew the nozzle while hot. Follow your printer's maintenance guide exactly, because over-tightening or working on it cold can damage it.

This is why we suggest keeping a spare nozzle made for your exact printer in our beginner toolkit. A clog stops being a week-long wait for parts.

How to stop it happening again

Bambu Lab also recommends a cold pull at least once a month as routine maintenance, especially when you switch between filament types. It takes ten minutes and keeps flow consistent.

Sources

Checked October 20, 2026: Prusa Knowledge Base, Cold pull (MK3 family), Cold pull (MINI) and Clogged nozzle; Bambu Lab Wiki, A1/A1 mini unclogging procedure, 3D printer clog and How to avoid nozzle clogs.

Your next step

Flowing again? If your prints now look hairy, read how to fix stringing. If they won't stay down, try why your first layer isn't sticking.