Running hot after rebuild

Hi Team,

I think I have developed a new problem with my loop. I have recently got myself a vertical GPU riser to try and prevent any damage from sag, so this involved a teardown of the loop to get a single hose made a bit longer. The teardown wasn't strictly necessary, but I figured I would flush the radiators out to try and get the annoying green colour our some more since my last post.

System info: 2x EK 360xFlow radiators (3x Noctua fans on each rad), Strix 3080 with Vector WB, Coolermaster CPU block, i7 10700, Corsair XD5 Pump/Res combo.

In the process, I took apart the whole loop, cleaned / flushed both radiators with a mild vinegar and hot water mix, flushed the shit out of them, ran distilled water through them and returned them to the loop. Otherwise I ran distilled water through the whole loop as a leak test and all went fine. I drained and refilled with OC Gear NoBS coolant, and have been running it since.

In today's gaming, I noticed the coolant temps were high. Normally sits around 50c during a session of BF6, but today it peaked at 58c. Also, I tried monitoring with HWinfo, and got a GPU temp of 81.7c and a hotspot of 106.5c, with a thermal limit triggered. CPU peaked at 95c!

Aside from my making the GPU vertically mounted, no other changes were done to the loop.

I know it's a hot day here in Brissie, but what have I done to it?

Thanks,

-Scott

 

air bubble somewhere?'

have you shaken the system and spun it around to try and get all the air out?

 

Your coolant was normally 50C and is now 58C???

Those are both WAY too hot for any system (60 is danger zone), and way too hot for your loop. My D5 Next is set to alarm (by default) above 45C coolant temp.

Your system is only putting about 400 - 450W into the loop, it should be able to handle that without drama with 2 x 360 rads.

I would immediately tear it back down and strip your CPU and GPU block and check the fins for junk trapped in them. Other than that, you need to rethink the air flow in your case, it seems like your rads are potentially starved for air.

 

Yep, shook / tilted it quite a bit during the filling process and topped up accordingly. Loop takes just over 1L of coolant and is reasonably good for no trapped air (my front X-flow rad helps with the inlet at the bottom, outlet at top and the top rad is laying flat).

*Sigh*. I was hoping I didn't have to do that. It is a royal PITA to break down, since it is such a tight build in the Fractal R6 case. My build is a sleeper. Airflow was what I believed to be OK for the case, 3x front rad fans (F12's) pulling cool air into front rad and case, 140 intake on the bottom, 140 exhaust at the rear, 3x top rad fans (A12x25's) pushing up and out. I do run a fairly quiet fan curve through fan control, so might need to push it a little harder.

I guess its time to open it all up again.

Before loop change (old photo when I first built it and was testing):


After loop change:

 

If everything's that hot, make sure your pump is running - and pumping - before you go pulling down
If your pump is on PWM control, turn it off and run it flat out. Software speed control on pumps is a pox and will lead you down the garden path a few times before you work out that it's just doing no duty.
I agree with Beast though - coolant is way too hot, even at 50C.

 

Thanks Juzz. I do have the pump on a curve. Do you suggest its ok for the pump to run 100% all the time? I read conflicting info previously. Assuming the pump shouldn't care as long as its not running dry. When I get home, I will grab some info on the curves and post here.

After exiting the game (removing the GPU load), the coolant temp fairly quickly returns to around 30c. So basically a couple of degrees above ambient.

When filling the loop, the pump was cranking with no apparent resistance, it drains the res very quickly (3-4 sec) into the loop. So when I fill, I power it on with a full filler bottle in hand which I squeeze into it as quickly as I can before it gets low, before powering off to fill the bottle and res again.

 

Yep, I just run them full-tilt all the time. Noise can be a consideration depending on the pump, more of an issue with DDCs. Some variants of the D5 have an onboard limiter which is handy. Most reviewers will come at it from a noise standpoint, not longevity. The D5 at least is an industrial pump - it's MTBF is rated on continuous usage at 100% duty. The ceramic bearings are happiest when spinning fast, and wicking the heat away (via the fluid) quickly.

If you're draining your res that quick at fill, and your coolant is coming back into range reasonably quickly when the load is off, it suggests the pump might be fine anyway.

Both blocks getting hot (assuming they're both good mounts and your paste isn't pumped-out and dried up) sort of points to just not enough capacity, airflow, or both.
I can't see your photos from here (my issue, not yours), but crossflow radiators will almost halve the heat transfer capacity compared to a standard 360 dual-pass, so you're at a bit of a deficit there anyway, and that might explain the 50C coolant temps pre-pulldown.

While you're pulling down, redo the CPU block mount and leave the 3080 out of the loop and boot the rig on the iGPU in the 10700. See what CPU-only does to your coolant temps. If it's out of the 30s, you're probably just struggling for capacity a bit

 

So you mean remove the GPU altogether and re-tube for this test??

 

Yep. Just use the iGPU in your CPU if you have the ability to. Then fang the CPU with Prime or something, and see how hot you can get your coolant

 

Might also be an idea to run the pump and all fans at max whilst load testing the system as this will tell you if the water and airflow are working as intended. Given you have a higher ambient, water temp for that system should still be under 45c or lower at max flow.
If that actually works out, then you just need to adjust your fan and pump settings to find a balance of cooling and noise. If it doesn't work (still running hot), you probably have an issue in the loop somewhere.

 

Thanks guys. I got home last night and just couldn't bring myself to drain the loop and strip it down - again, so maybe a weekend project. I just put fresh coolant into it, and don't have any more so I will drain the loop through a coffee filter paper to catch any of the crud that might be in there, hopefully none, before putting it back in.

At this stage, based on advice around airflow, I am considering a bigger case, since the R6 is tight AF. Thinking I like the Define 7 XL.

 

Just wanted to throw it out there, perhaps a bad mounting with the waterblock on the CPU ?

 

When I do get round to pulling it apart again, it will be getting a good clean and re-pasting. Strangely I didn't touch either of the water blocks during the last teardown. Maybe they got some dislodged crud stuck in them as part of being flushed. I will report back when I do the testing.

 

Before pulling it apart, as Juzz has said just run the pump flat out for a minute or 2, you might have some serious air in the system consuming half the radiators space. Add to that the radiators are only cross flow (single pass vs dual pass normal radiators) if theres a heap of air you basiacally have no cooling.

Whats the ambient temp in the room the pc is in?

 

Let's say mid-high 20's ordinarily. Coolant temp at idle sits around 30c.

 

That could also be the case, but it wouldn't solve the problem of over temp coolant. If anything a better mount would make it worse.

 

Presuming you have no HDD. Eliminate any trapped air first, before dismantling!

• Run you PC as is for 30 minutes, measure the temps.
• Run the pump at 100% for 30 minutes, measure the temp
• Reduce the pump to 80% than
  • Lean the PC on its side like 45 degrees to each side for 15 minutes (every few minutes lean it to the other side while it is on) I use few stacks of heavy books to lean the pc to, so I am not holding it
  • Finally pick up the PC and Tilt the PC front and the back a few times.

The above should have eliminated or expelled the trapped air if it was there, measure the temp, if no or little improvement, first remount the cpu and gpu, test again for temp.

If there is some improvement after remounting than try the lean and tilt test again to untrap the remaining air that was inside the cpu and gpu block.

If no improvement than teardown is on the cards.

 

With 50deg fluid temps, i wouldnt be leaning to bad mounts since the waters taking the heat from the cpu/gpu, it just cant get rid of it once it has it.

 

yeah check the fans are spinning up to full rpm ? and that the radiators aren't all caked up with a layer of dust ?

 

Where are you getting that temperature reading from? Do you use a Corsair Commander Pro or similar to control the pump and see the liquid temp?