The big day of fixes.

So its one year plus down the line after purchase and it was getting more and more evident that my Wanhao 3D printer was getting a little worse for wear around the edges.  The right side extruder fan was missing a blade, and the cooling fan for the mother board was also not running. And as for both the extruder heads. Well…


Both the heads, due to previous ‘on the fly’ fixes had all of there insulation pulled off (effecting temperature regulation) and the inclusion of incorrectly sized nozzles, and lack of PTEF insert where leaking baldy causing messy prints (see my previous post.) On top of all this I still needed to change the right  thermocouple.  So, time for a long over due overhaul.

Here we have (from left) the new thermocouple, some Kapton heat resistant tape, two new hot ends plus PTEF inserts, and the insulation strips for the hot end blocks.  All available from the Wanhao UK site (note you may have to ask them for the insulation strips via e-mail as they are not listed)


To start with I dissembled the left hand extruder assembly. From there removing the nozzle was difficult due to melted and reset PLA. This was solved by preheating the end and using two big pairs of pliers to undo it (WANING! be careful not to burn yourself. The moment the nozzle comes loose turn the machine off!) then I cleaned all the leaked plastic off the block, inserted the PTEF’s into the nozzles and attached the new nozzles into the block. Next i added the insulation strips and secured them with Kapton tape.


I reattached the hot end and reassembled the extruder assembly. before repeating the same with right extruder assembly (I recommend taking care of each extruder assembly one at a time so not to get all the bits muddled up, as it gets very fiddly with all the small bits) however on the right hand side I changed the thermocouple also while the extruder block was apart.

Changing the thermocouple requires taking the black spiral cover of the bunch of  wired leading from the duel extruder assembly to the underside of the machine and carefully snipping the cable ties. From there you can locate the thermocouple and easily swap it out. This requires nothing more than a small 0.4mm flat head screwdriver (take a mental note of the colours on the wires of the old thermocouple before  swapping it out to make sure you are reconnecting them the correct way round) and the supplied Alan key to change the thermocouple on the extruder block. Afterwards use some new cable ties to bunch all the wires together again. Personally I did not re-attach the black spiral cover as it seems unhelpful and only there for the look of the thing. But its up to you.

When reconnecting the second hot end to the hot end mount block you are confronted with the issue of getting the print heads level. Please go and see my Facebook page ( for a link to a useful 3D printable level free from Thingiverse to help with this.

After changing the right hand fan (very easy) now its all back together and looking good!


Finally i changed the motherboard cooling fan. Its the same gig as changing the thermocouple. Just make note of those wires to keep them the right way round!



And upon firing my Wanhao up and doing a test print. Lovely! The quality is back! But do note, this quality was only achievable after a bunch of other upgrades. Please see these older blog links:

It’s here! The tried and tested simple guide to reliable PLA prints on the Wanhao Duplicator 4. Part 1
The tried and tested simple guide to reliable PLA prints on the Wanhao Duplicator 4. Part 2
The tried and tested simple guide to reliable PLA prints on the Wanhao Duplicator 4. Part 3

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Thanks for reading this rather long post! I shall being providing some next and interesting topics for you very soon. Watch this blog!