# How to refill an AIO ? (Cooler Master Nepton 240M)



## Mr.Quinster (Feb 15, 2020)

I have this Cooler Master Nepton 240M for 5 years now and is out of warranty. It is making weird noises because of bubbles. I saw there was a cap on it with void warranty so i thought this must be the refill cap. But after a long time of prying it still hasn't opened up. Has someone done this before because i cant seem to find any yt videos on these cooler master models being refilled.


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## Ferrum Master (Feb 15, 2020)

Put it up so the vent is at highest point. Pour in some coolant.


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## Chrispy_ (Feb 15, 2020)

You're not going to get that fill port off without trashing the radiator. It's likely glued or soldered and if you twist it too hard I'd put money on the end tank cracking before the filler cap moves. Don't search for YT videos of people refilling a Nepton 240M, look for videos of people replacing the tubing on AIOs. You'll get more examples and tips that way.

The only way to refill most of these AIOs is to remove tubing (it looks like you should be able to cut the existing hose off) and replace it with the standard clear tubing and hose clamps as used in most custom loops. Not only will you be able to see bubbles, you'll be able to tell when it's time for new coolant. As for tubing diameter, you'll probably want to cut off the existing tubing first and measure the barbs on the block and radiator - go for the closest ID tubing that is smaller than the barbs and use dish-soap to lubricate the new tubing so that it fits. If it were me, I'd add a T-piece and a valve or end cap to make refilling and bleeding it a 2 minute job (instead of a 2-hour job) the next time you need to do it.

You'll want to drain the system completely, flush it as much as you can in reverse to try and de-gunk it and then refill with anti-corrosion inhibitor and biocide because you'll be dealing with mixed metals in an AIO. Too much anti-corrosion and your system will gunk up, too little and it'll corrode - so follow the instructions on the bottle carefully!

https://www.aquatuning.co.uk/water-...8/phobya-2-way-ball-valve-g1/4-knurled?c=2672 - an example of what I'd use as a fill port off a T-piece.


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## Mr.Quinster (Feb 15, 2020)

Thanks for the fast responses guys! You have really helped me, i am now going to the hardware store to get some new tubing.


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## EarthDog (Feb 15, 2020)

Buy another aio....

...part of the reason users buy an aio is because they tend to have less chance of leaking than a custom loop. If that is a concern and you cant get the fillport open, , go buy another. It lived a good life.


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## gasolina (Feb 15, 2020)

i just open my aio block and fill it , close it, let it run if any noise happens i stop it then open it up and refill . I'm using DIY AIOs for my 5 rigs no leak so far since i use all aluminum ( aluminum plated block, aluminum radiator and silicone tube )


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## sneekypeet (Feb 15, 2020)

The easiest way into an aio is through the cold plate, if you have the proper tools, as mentioned above.


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## JKo (Sep 29, 2020)

Mr.Quinster said:


> I have this Cooler Master Nepton 240M for 5 years now and is out of warranty. It is making weird noises because of bubbles. I saw there was a cap on it with void warranty so i thought this must be the refill cap. But after a long time of prying it still hasn't opened up. Has someone done this before because i cant seem to find any yt videos on these cooler master models being refilled.




This is probably too late for your needs, but for future reference... the Nepton has a rubber plug under that "warranty void if removed" sticker, and under the plug there's a screw with a regular phillips head (pic below). Just pry off the rubber plug with a small screwdriver or with a small knife and undo the screw to empty/rinse/refill. Definitely not the fastest way to do it though, took at least 2 hours with my Nepton 120XL. If I ever need to do it again I'll definitely add a T-piece to the tubing to let out air from one point while pushing water in from another.

The liquid that came out was very clean, smelled like regular anti-freeze from a car, and had a greenish tint to it. It wasn't even nearly full after being in use for over 5 years. You could hear that there was air in there when it was running, and cpu temps were creeping up. I rinsed it with distilled water (no gunk came out), then filled with 1/3 anti-freeze mix that should be good for mixed metals.


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## DeathtoGnomes (Sep 29, 2020)

I have the same cooler, its been 6 years and it seems to be still going strong. I think after reading this thread I'll see about refilling it.


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## hat (Sep 29, 2020)

I agree with the others. Cut the hose off, get new hoses and clamps, and add a T piece. Or a reservoir. A res will make filling it back up a shitton easier and it will improve temps, too.


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## silkstone (Sep 29, 2020)

You could also just place it so that the tubing on the rad is at the bottom. Even with limited liquid, it'll work well enough and not be noisy. 
The amount of liquid in the cooler 'should' be a huge deal as they work based on the thermal transfer properties, rather than the specific heat capacity.

I have an old Seidon that is 5+ years old and am running that way. My only concern would be when there isn't enough liquid to form a complete loop.


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## John Naylor (Sep 29, 2020)

With all copper OLC Type AIOs being available for as long as they have, I don't understand why CLC usage has continued... Corrosion inhibitors have a useful life of 18-24 months.    Changing the coolant doesn't remove the crud.

https://  www.youtube.com/watch?reload=9&v=a_r4tWpMHHI

For those interested in the science








						Galvanic Corrosion Explored
					

Ahh the joy of mixing metals in a closed water loop…:)  While many water coolers have had excellent success with running copper/brass/nickel over the years with plain water, we have seen many…




					martinsliquidlab.wordpress.com


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## de.das.dude (Sep 29, 2020)

silkstone said:


> You could also just place it so that the tubing on the rad is at the bottom. Even with limited liquid, it'll work well enough and not be noisy.
> The amount of liquid in the cooler 'should' be a huge deal as they work based on the thermal transfer properties, rather than the specific heat capacity.
> 
> I have an old Seidon that is 5+ years old and am running that way. My only concern would be when there isn't enough liquid to form a complete loop.



ah a man of culture who has watched the GN video too.

Guys, wont getting the tubes off be harder?



John Naylor said:


> With all copper OLC Type AIOs being available for as long as they have, I don't understand why CLC usage has continued... Corrosion inhibitors have a useful life of 18-24 months.    Changing the coolant doesn't remove the crud.
> 
> https://  www.youtube.com/watch?reload=9&v=a_r4tWpMHHI
> 
> ...




that is from 2012. a lot has changed since then. AIOs now have a shelf life of 6 year. 
Also distilled water doesnt cause galvanic corrosion. ALSO.. copper and aluminuim quickly oxidizes and creates a protective layer around itself which inhibits galvanic corrosion.
Im pretty sure the blocks and rads spent enough time exposed to the air to develop that layer.


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## Deleted member 24505 (Sep 29, 2020)

Take a pipe off, submerge it in fluid till its full, put pipe back on, clamp it


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## Fry178 (Sep 29, 2020)

@de.das.dude
guess it has eluded you that OLC (AIO) are now in the same price range as CLC, while they will offer easier flush/refill/part replacement/top-off etc,
not even talking about EK/Alphacool etc using copper rads, removing alu from the loop/

So outside the Corsair stuff (5y warranty that covers ANY damages to the pc),
or some ultra cheap build, not making sense to stick with CLC.


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## de.das.dude (Sep 30, 2020)

Fry178 said:


> @de.das.dude
> guess it has eluded you that OLC (AIO) are now in the same price range as CLC, w



unfortunately, thats not the same everywhere. And not everyone is an american


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## Deleted member 193596 (Sep 30, 2020)

sell it for 15 bucks and buy a new one


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## Fry178 (Oct 1, 2020)

@de.das.dude
never said it, nor did i mention a price, but its also not the minority (with decent prices) on this planet that can get decent prices on HW.

how about Europe with places that have higher import/vat fees,
germany (20% vat) lists 240s from Corsair and the like for 80E, the Eisbaer is 88E,
thats not even 10US$ more to have 1. a res with window , 2. copper rad, 3. a pump with adjustable rpm, 4. "standard" G1/4 parts.


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## JKo (Oct 1, 2020)

For me refilling the Nepton 120XL meant that I didn't need to spend way over 100€ (here in Finland with 24% vat) on an adequate new cooling solution that would fit in my mini-ITX case. Also rotating the rad so that the tubing is at the bottom is not possible without some heavy modifications.

Definitely going for an OLC with a copper rad if the Nepton can't handle the next cpu upgrade, or if the pump finally fails.


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## Chrispy_ (Oct 1, 2020)

Ugh, this thread's been necro'd and I'm getting pinged.

Yeah, you can get the manufacturer's fill port screw undone but it's a self-tapping thread so once you've undone it and re-tightened it you've lost the seal and you'll get air in the system over the coming weeks/months. I guess you can tighten it even harder to get another seal but there's only a very limited number of times you can do that (like, 0-2 times) before it's stripped and you have to trash the whole thing.


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## JKo (Oct 1, 2020)

Chrispy_ said:


> Ugh, this thread's been necro'd and I'm getting pinged.
> 
> Yeah, you can get the manufacturer's fill port screw undone but it's a self-tapping thread so once you've undone it and re-tightened it you've lost the seal and you'll get air in the system over the coming weeks/months. I guess you can tighten it even harder to get another seal but there's only a very limited number of times you can do that (like, 0-2 times) before it's stripped and you have to trash the whole thing.



Interesting, it didn't look like a self tapping screw to me on the Nepton. I could be wrong tho. It did have a washer type rubber seal on it, so it's not relying on the threads alone.

Anyway, I undid it and retightened it maybe three or four times in my bleeding process. I guess I'll find out soon enough if it's fubar'd.

PS. Loving your avatar. For great justice.


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## Chrispy_ (Oct 1, 2020)

JKo said:


> Interesting, it didn't look like a self tapping screw to me on the Nepton. I could be wrong tho. It did have a washer type rubber seal on it, so it's not relying on the threads alone.
> 
> Anyway, I undid it and retightened it maybe three or four times in my bleeding process. I guess I'll find out soon enough if it's fubar'd.
> 
> PS. Loving your avatar. For great justice.


OK no, if it has a rubber washer it's because it's a regular screw and compressing the washer is what provides the seal - that's very much a re-usable design.

I guess it's possible that the port designs aren't identical between different models, or that CM have revised the design since I did a teardown on an old Nepton about 3 years ago. Mine was either soldered or just self-tapping because for whatever reason it gouged a huge chunk out of the radiator and stuck to the screw. Worked for me anyway as the radiator was the part of the AIO that I was trying to swap out from a 240mm to a 140mm one.


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