Problem w/Flattening on one tubing link. Please Advise!

Above are the Pics of my system that I just redone. As you can see there are no kinks or sharp bends. I set this up for optimal one loop water distribution in this case.

Well my tubing is two different kinds:
RES-PUMP, PUMP-CPU AND CPU-GPU are all Tygon ½” ID / ¾”OD

GPU-RAD & RAD-RES are Tygon ½” ID / 5/8” OD
The reason for the smaller OD is because of the holes into the case & grommet size.

Well the GPU-RAD is fine but the RAD to the RES is flattening at the top near the radiator. I don’t understand this. Just near the top of the case the tuning is almost flat and then is fine for the rest of the way down draining into the RES.

It is so flat that it is defiantly restricting flow. The only thing I can think of it that the speed of the fluid increases after it comes out of the radiator and this would slightly increase the pressure drop when it comes out of the tube into the reservoir. This pressure drop and the thin wall of the 5/8” tubing is causing the flattening.
Is this even close?

My 2 options are to try and use anti kink coils/wrap or just go with the stiffer ¾” Tygon w/out a grommet.

Any thoughts about this???

you really shouldn't be using different sized tubing, why not just make the top holes in the case larger?


Going from large to smaller tubing will not just automatically make the same volume of water flow faster because the tubes are smaller, it effectively slows down the entire loop, and puts pressure in certain spots that normally would be fine, I'd say your flat tubing is a prime example of this.

Phrenetical said:

you really shouldn't be using different sized tubing, why not just make the top holes in the case larger?


Going from large to smaller tubing will not just automatically make the same volume of water flow faster because the tubes are smaller, it effectively slows down the entire loop, and puts pressure in certain spots that normally would be fine, I'd say your flat tubing is a prime example of this.

Click to expand...

Is this true even though both sets of tubing are 1/2" ID?

Phrenetical said:

you really shouldn't be using different sized tubing, why not just make the top holes in the case larger?


Going from large to smaller tubing will not just automatically make the same volume of water flow faster because the tubes are smaller, it effectively slows down the entire loop, and puts pressure in certain spots that normally would be fine, I'd say your flat tubing is a prime example of this.

Click to expand...

all tubing in my case is 1/2" ID which means that they all have the same inside diameter. The only differnce is the wall thickness. It's ok I have a copy of hooked on phonics you can borrow. LOL!

it looks good to me from the pictures, but maybe try adding zip ties to the flat part or spring coils.

Phrenetical said:

you really shouldn't be using different sized tubing, why not just make the top holes in the case larger?


Going from large to smaller tubing will not just automatically make the same volume of water flow faster because the tubes are smaller, it effectively slows down the entire loop, and puts pressure in certain spots that normally would be fine, I'd say your flat tubing is a prime example of this.

Click to expand...

there both 1/2" ID so things are fine in the sense your talking about.

Im not sure if this works...

sometimes cutting a piece of tube that is a bit longer (or shorter) than before and puting it the same section helps to make the tube round again.


Otherwise its very difficult to find smart coils that cover a 1/2" ID 3/4" OD tube.

(we cant see the "flat" tube that you are talking about in the pics can we?)

The 1/16" walled Tygon is VERY soft and pliable, and it can and will expand and flatten out. Especially with a powerful pump. Mysuggestion would be to get yourself 1" hole saw, and widen up the holes in the top of the case.Then use some 1/8" walled tubing.

Jas said:

The 1/16" walled Tygon is VERY soft and pliable, and it can and will expand and flatten out. Especially with a powerful pump. Mysuggestion would be to get yourself 1" hole saw, and widen up the holes in the top of the case.Then use some 1/8" walled tubing.

Click to expand...

man, I just got this whole rig together. My wife is going to kill me when I start ripping it apart. Well just ordered more 3/4" tubing. I new this was going to be the soulution but just needed someone else to tell me.

LAGAMM said:

man, I just got this whole rig together. My wife is going to kill me when I start ripping it apart. Well just ordered more 3/4" tubing. I new this was going to be the soulution but just needed someone else to tell me.

Click to expand...

Don't feel bad, it's all part of the fun. Longest I've had a loop together is probably 3 or 4 months. I'm always changing stuff around, or getting new ideas.

And since no one else said it....Nice looking loop.

I've got a similar problem - two sections of tubing have flattened. I'm using 3/8" ID and 1/2" OD Tygon, so it's pretty flexible in the first place. When I filled and leak tested it, everything was fine, it was only when it ran under load and warmed up that it flattened.



The flat pieces are those running to and from the graphics card. Would coils help with this? And other suggestions?

Holy thread revival! Good use of search though.

Coils or zipties would help. Bitspower 45 degree fitting from the CPU to the GPU would help too.

That is thin walled tubing, only 1/16" on each side. So it's hard to stop kinking.

I can see it kinking on the hose outside the case too............

You're right, I hadn't noticed that one... Temp wise it's doing that job, the goal is quiet rather than amazing performance, but obviously I want to get it "right" too. This is only my second watercooling setup, and the first used the really stiff stuff Zalman put out with their kits.

Will give coils a try, but the lesson I've learnt here is that for my third setup (whenever that may be...) I'll be using thicker walled tubing.

7/16 ID and 5/8 OD is very popular. I use 1/2 3/4 for best massive tubing.