TRYING TO FIND PROPER COOLANT AND APPROXIMATE AMOUNT NEEDED FOR FILLING AN HP Z820 LIQUID COOLER

[gman2154]

I have a few  HP Z820 Liquid Cooling CPU Heatsink 635869 that i am refurbishing, and after investigating ad nauseum can't find a definitive answer to: 1. what coolant should i use to refill these (HP says propylene glycol )?  2. are there premixed version of this available (Thermaltake or the like)? 3. What portions should i mix (If i have to) glycol to distilled or deionized water? 4. approximately how much coolant do i need per heatsink? Anybody out there still fooling around with these? Any help is appreciated!

[DGroves]

any water-cooling vender who specializes in custom water loop parts will have all items that you need in general AIO systems like the HP units will use around 60/80 cc's of coolant below are links to three of the more popular venders

you might also want to modify the HP radiators to add a water filling/air purge fitting

https://www.frozencpu.com/cat/l1/g30/Liquid_Cooling.html

https://modmymods.com/

https://www.performance-pcs.com/

[gman2154]

Thanks, sometimes I overthink these things! I couldn't quite find the fittings for intake/bubble release as i only pulled the copper plate off and filled from there. Seemed to take about an ounce or 30 cc's as you mentioned. I still hear a little sloshing around. Does the coolant expand much as it is heated?

[DGroves]

NO, you should not be able to hear sloshing of the liquid this indicates that there is still air in the AIO

if you have not modified the AIO for a fill/air purge inlet then the proper way to fill is to immerse the radiator, hoses  and cpu/pump block fully in a container of the cooling mixture and then power on the pump and rotate the radiator so that all air bubbles are removed and then reattach the cooling plate that you removed while it's still fully immersed

https://www.youtube.com/watch?v=ElYtpezZASU

[SDH]

Attached are 4 images from a prior post related to the Z420 liquid cooler, which some of us have adapted to use in the Z620 workstations also.  This info mainly is from another related post, with some clarifications.  I have no idea if the Z820 liquid cooler can have its top easily removed the same way to allow access to a filler port screw from above... I would think so.  My guess is that it is best to stay out of the inner bottom pump chamber given the easy access through the silver filler screw from above.  I'd fill very carefully with a syringe through that access port.  See also the attached PDF of the original post, below:

Stock Z420 liquid cooler from belowOnly remove 2 screws...Top access now to the filler screwBottom of the filler screw...