Unable to remove heatsink out of MK3 extruder  

Honorable Member

My MK3 has a clogged nozzle and I want to disassemble the hotend.

But I cannot remove it from the printed parts.

I am stuck at the part shown in this video:

Unlike in the video, my heatsink does not come off the extruder, I have already used somewhat 'unreasonable' force, but have not yet broken anything! 😛

I removed the heater and heat sensor to protect them during all the wiggling, the heat sink moves freely away from the extruder body but the top end with the PTFE tube does not pull out.

Any ideas what causes this and how to get around that problem?


Posted : 28/09/2018 11:42 am
Reputable Member

Sometimes I have problem with the PTFE tube below the extruder gears being wallowed out and deformed from the filament passing through it so it jams right below the extruder gears.

If that happens I get enough wiggle room to push collet down and remove the hotend and leave the PFTE tube behind. Then if I still can't remove the PFTE tube under reasonable force I just sacrifice it by pushing up and snipping it off then replacing the tube.

Hope that helps,


Posted : 28/09/2018 4:48 pm
Estimable Member

It is a tight fit into the extruder carriage. If you have had the hot end at a high temperature the some of the plastic or ptfe tube could have warped

Posted : 28/09/2018 5:31 pm
Honorable Member

Thank you, Neal and Robin!

I used even more brute force and it came out. I think the plastic parts were either badly shaped from the start, or they warped later on.
The PTFE tube was not stuck.

Unfortunately, the clogging has recurred after cleaning the hotend out.

I think it might be the filament. It printed fine with carbon-PLA and clogged again after changing filament to the previous PLA roll.

I often use carbon filament for a while to clear out the nozzle by abrasion (it's a hardened steel nozzle).

I have noticed inconsistencies in colour with this particular filament, resulting in bands of lighter and darker colour during 12-18hr prints. Maybe the problem is not just colour variation, but poorly mixed plastic?

I have also had some "Fan error' problems a few days ago, until I turned off the fan monitoring. I could not see any fan problems occurring, but maybe there is an intermittent fan failure due to a breaking cable.

For now, I'll try the same print entirely from carbon-PLA. If it clogs again, then it's not due to the filament.

Posted : 28/09/2018 6:20 pm
New Member


I have a similar problem. This PLA fillament (From PRUSA) often stuck when I was removing it, but in this case, it got stuck really bad and also noises from gears were heard.. I tried removing it, but fillament broke off. I think it got stuck just before print was finished since print was not ok (lack of flow).

Now I can't remove the heatsink from the extruder carriage. I can see PTFE tube move for a 1-2 mm but it won't go out. I used more than reasonable force even with leverage from pliers.

I didn't have problems with other fillaments or types before. For the next step I will try to drill out the clogged plastic with 1mm drill. Your thoughts?

Posted : 28/11/2018 4:40 pm
New Member

Fixed. I was able to get fillament out. I carefully drilled in on the top of the stucked fillament with 1.5mm drill until after 3-5mm in, drill captured fillament so I was able to pull it out. After that I was able to remove heatsink out of MK3 extruder.

Posted : 29/11/2018 9:05 am
iy meng.l
New Member

Hi guys, is brute force the only way to do this? It feels so awkward and unnatural and im really afraid of breaking something.

Ive seen some videos of people pushing and pulling the heat sink at the same time, butit doesnt work for me 🙁

Posted : 29/11/2018 12:38 pm
Estimable Member

Hi guys!
Been there... and there is an easy solution!
I only have a minute.
don't pull hard, lift it half way out of the extruder, then stick a flat screw driver under the top part of the heatsink (the narrow flange) and gently lever it out of the extruder plastic part until you can pull it down.

Basically the PTFE tube is holding it in, and you need to work against it to get it a little out of the plastic part before you can pull it down.
Check the manual, they say use pliers, but the screw driver works better and easier.


Posted : 29/11/2018 1:33 pm
New Member

I used the above method. Use a small flat head screwdriver and leverage the hot end out. Do it slowly and wiggle the hotend up and down slightly eventually it will come out easily. The PTFE tube is a little jammed. (This is for the MK3 only). I can not vouch for the other models. But this technique worked for me on the MK3. 

Posted : 26/11/2019 12:55 am

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