Help needed with Powermac G5 quad 2.5 dp LCS

Cyclone740

Tinkerer
Oct 29, 2023
108
8
18
OK, so I am working on restoring a PowerMac G5 quadcore dual 2.5 cpu double pump liquid cooled system for a friend, and I am currently at the point where I have removed the radiator, tubes and pumps from the system, and I have emptied and cleaned the loops, and repaired the radiator as best I can.

Now is where I need some help, I am trying to use the right coolant for the loops but I just want to confirm what the conditions are for it to be good. I have found some replacement coolant, but I am wanting to have some help with confirming if it is OK to use in the system. I am aware that it needs to be Glycol free, and it is, I just want to confirm that it is fine to use the coolant as it is green in colour rather than red. I understand that I will need to dilute it with some demineralised water, and regarding that process, could someone please tell me what the ratio I should use in my system is?
Also what is the stuff that is being used to seal the ends of the tubes with the rest of the construction? Also what is a good tube sealant for using in the situation, as I am going to be using a hyperdermic needle to help bleed the system of air pockets as is said to do in the guide, possibly also replacing the old tubes with new ones. Are the ones I have shown a good option?

Shown below are the pictures relatibg to this post.
20250609_091857.jpg
20250609_091845.jpg
20250606_132157.jpg
20250606_132215.jpg
Screenshot_20250606_131926_Chrome.jpg
Screenshot_20250606_131209_Chrome.jpg
20250606_132315.jpg


As i am going to be passing the place that I plan on picking up the stuff from tomorrow morning, any of this help would be a great help, I am trying to help save this machine, because she was of the mindset that it would just be better and easier and cheaper if she just gutted it and slapped a modern computer in it, which I managed to tell her is a lot more costly and difficult than what she thinks. Also the system works great, it is just the coolant needs to be replaced.
 

phunguss

Active Tinkerer
Dec 24, 2023
387
335
63
Stillwater, MN
I think most automobile antifreeze is usually mix 1:1. Unless you purchase the specific no-mix version. I don't think the antifreeze is so much to prevent freezing of the coolant, but to raise the boiling temperature. Although, when it is working, it should never get to boiling temps anyway, which means you could get by with just water on a temporary basis.

I have all 3 versions of the liquid cooling systems, but they were disassembled in January of 2024, and I have not gotten back to them yet to reassemble.
 
  • Like
Reactions: Cyclone740

Cyclone740

Tinkerer
Oct 29, 2023
108
8
18
I think most automobile antifreeze is usually mix 1:1. Unless you purchase the specific no-mix version. I don't think the antifreeze is so much to prevent freezing of the coolant, but to raise the boiling temperature. Although, when it is working, it should never get to boiling temps anyway, which means you could get by with just water on a temporary basis.

I have all 3 versions of the liquid cooling systems, but they were disassembled in January of 2024, and I have not gotten back to them yet to reassemble.
Thank you so much for you fast response, this is very helpful to know.

Can I ask what the size for the tubes is for the ones that are connected to the CPU block? I feel like replacing the tubes is a good move here because I feel like there was some serious damage done to them in the disassembly process.

Also, is there something that I should look out for when selecting the type of tubing that I intend of using like I get using the clear stuff but what key things should I check for before getting it.

Also, will the coolant I have shown in the picture be OK I feel like that would be a good option because it is the without Glycol, and is also non corrosive to the aluminium and copper from what I understand.

I was also wondering if there is a recommended mix ratio for the system or not as this is the pure consentrated coolant and needs to have some demineralised water added?

What about the epoxy sealant stuff, is it needed or is it just Apple being Apple and added something unnecessary?

And what about the type of sealant used to patch the tiny holes that might be made when using the needles to bleed the loops?

Again thank you so much for your help so far.