PowerMac G5 Quad "The New Blood Mod" - A guide to flushing, modifying and refilling the dual-pump cooling system.

[dorkshoei]

Oddly I only got 250ml out of both of my radiators. Before I disassembled I could hear coolant moving if I shook the assembly which implied the presence of air. No leaks.

I'm flushing them using a submersible pump and a warm vinegar solution and I definitely appeared to have a blockage on one side, however it cleared fairly quickly.

The pump rate is fairly low, 5.6 liters per minute and that flow cannot be sustained through the radiator. I'm not seeing any debris. I'll have to try the 1/2 fill, connect input&output and shake method. See if anything comes out then.

I put mine on the shelf. I'll get back to it later. I clearly have a blockage in one of the halves. If I blow compressed air through the flow rate will increase to match the good half for a while but then it slows again to maybe 1/2 the rate of the good half. I ran vinegar, aluminum safe radiator cleaning solution etc through it (using the pump) but no dice.

 

[demik]

I put mine on the shelf. I'll get back to it later. I clearly have a blockage in one of the halves. If I blow compressed air through the flow rate will increase to match the good half for a while but then it slows again to maybe 1/2 the rate of the good half. I ran vinegar, aluminum safe radiator cleaning solution etc through it (using the pump) but no dice.

Just worked on mine today. One half looked like it leaked and there was not enough coolant. Although even using gravity, I couldn't manage to get any liquid to flow through the pump. (it was running). I was able however to blow air through all the system and that went fine.

At this point i'm thinking the pump impeller are defective or something similar

 

[Paralel]

So CircuitBored, could you give us an update on how your loop is running?
I have a very weird problem. The lcs seems to build up gas after time. I completely flushed and refilled the loop three times now. Every time I renewed the coolant, the lcs builds up massive air pockets that I can see through the clear tubing.

If I detach the tubing, the lcs literally explodes on me. I am using computer-grade biocide of course, so I have absolutely no idea why the lcs does that. I have a good amount of experience with liquid cooling, I'm doing this in the PC realm for seven years now, I have built multiple systems with custom water cooling. Never ever have I experienced something like this in a PC. I'm at a point now where I start thinking about 1. air cooling the Quad or 2. even build a new lcs scrapping all the G5s parts besides the copper CPU heat sinks to get rid of any contamination.

How long does it take for the gas to build up? If its less than an hour to a few hours, it's a chemical reaction. If it's 8-12 hours to a day to build up, it could be biological.

 

[zChris]

Hello,

Im currently trying to do this mod but i have some question regarding the pumps. The lowerhalf that is springloaded, is that supposed to be removed and not used?

 

[zChris]

To answer my own question yes you need the lowerhalf. Im done with the mod and the computer is on test atm. Currently it passed the thermal calibration tests serveral times.

 

[zChris]

After have had the computer max loaded for about 1.5h the temperature reached 42C on CPU A and 50C on CPU B. I think thats seems to show a success.
The command i used for maxing the cpuload was 10 instances of "yes > /dev/null &".

 

[CircuitBored]

To answer my own question yes you need the lowerhalf. Im done with the mod and the computer is on test atm. Currently it passed the thermal calibration tests serveral times.

I am so sorry for not replying in time! I am very glad that you were able to work it out. Enjoy your revitalised Quad.