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Lack of Waterflow in System

I just put my friend’s PC together and started to bleed the water cooling system.
Unfortunately, there isn’t much water flowing.
Does anyone happen to have an idea?
Thanks in advance.



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The Y fitting allows the water to bypass the reservoir.

Ignore this

I’ve never once worked with water cooling, so I’m probably not helpful.

That said, I have free time so I’ll do my best.

I made a diagram to aid in communication.

Shadow-r Waterflow-Labled

Green, as I understand it, is pressurized from the pump until it dumps into the reservoir.

Violet, for lack of a better phrase, is gravity fed.

Blue I can’t tell where it leads*.

*Question: The inlet/outlet for the front mounted radiator, do I see a T junction? Or does the outlet feed around to the top of the reservoir, as indicated by the blue arrow.

The Y fitting goes to a dead end on one end. It’s a drain port.

There’s no front mounted radiator
water goes as follows:
reservoir>Gravity to pump>gpu>cpu>rad>reservoir
the tube to the top is a fillport (with a y-conneter in the form of the reservoir) and the bottom is a drain port

hope that helps

P.S. CPU Block and Pump are reused from the previous build (Fury X was separate)

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Check that you’re not flowing backwards through one of the blocks. You’ll get significantly more pressure drop if you do something like that.

When you say there isnt much water flowing, that doesnt give much indication to how much water there is flowing. You dont need a ton of flow in a loop to work effectively. Can you make a short video?


Did you open that block to clean it? It might just have a little crud in it.

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I did connect the GPU block the wrong way around, but I fixed it and nothing changed.

I say that there’s not much flow because the pump (Swiftec MCP 655)on level 5 is pumping less water than it used to on level 1 (now there’s zero water flow on 1). I can try to catch it on video.

Also, I can try to bleed it over night and benchmark temps tomorrow

Furthermore, I didn’t clean the block. I just looked into the holes and saw nothing.
The loop got fresh coolant every year, so I don’t thing there’s going to be much in the block.

Video shows max water flow

Looks like its still getting air out of the system but you may need to tilt the whole system around to get the air to start moving. You could be experiencing a bit of an air lock due to lack of velocity in the radiator.

It might be a PITA but I would pull that pump too and verify its producing the flow expected. The flow you show isnt bad for the system but is bad if thats as high as it goes.

I’d still pull that CPU block apart and verify theres nothing restricting flow there.

Drain the loop down and test flow through each component in the loop by pumping into a bucket one at a time until you figure out where your restriction is.


I agree with @Adubs. With a lot of my larger builds if I had spots where air could get caught it was an issue. Id start with tilting it back far as you can. so the radiator ports are the highest point in the system to try and bleed it, that’s always a tough one with top mounted radiators.
Then tilt it back or lay on its back after filling res to not draw more air in. then tilt to front and towards you. etc. 2 or three times till you get better flow. May have to stop and restart pump a few times in different positions but I would definitely expect more flow than in your video.
Don’t mean to list so many steps if you know about it just try to be through.

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I’ve always done that also. At the very least it helps speed up the process so you don’t have to wait for those bubbles to clear out on their own. Depending on the size of the loop that can sometimes take quite a while.


Thank you people, I’ll do that tomorrow

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After throwing my brain at this problem for the day, I had a few ideas to apply the concepts discussed above. (I can show you the pictures, if you like)
With disconnecting all the parts and bridging them with various utensils, I was able to isolate the CPU block as the perpetrator.
Thank you for the help.

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I did think of one more thing… do we know the flow rate and head pressure of the pump? I may have missed it.

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well, I’ve used that pump in various loops and always had much more flow than that.
Therefore there must be an issue with the loop

Ok got ya. Just an idea I had. I always do the KISS method lol

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wtf is the KISS method if I may ask so bluntly?

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Keep It Simple an Stupid… always check my basics is the jist of it.

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So, next question:
clean it or trash it?

Id try cleaning first. never know…and your set up to test

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