Re-using/ Re-purposing the G5 Water cooling system

[minihack]

Hi,

This is going to be a slow burning thread, so patience required (!), but I thought it might be of interest and worth a post or two.

Recently I got hold of two defective G5 2.7GHZ dual machines. From these two I actually got one working really well and have overhauled for sale. The other though is dreadful.....a nice case (well, that's what I bought them for really) but a cooling system malfunction took out the power supply big style.

The thing is though having only seen air cooled Mac.s I was really interested by the lovely looking water cooler in both machines. The working one I re-furbished, but on the spares machine I decided that the water cooler is too good to throw away. It has a brilliant little 140 mm aluminium radiator that looks bullet proof (pic attached). It also has an interesting pump. The pump is labelled Delphi, but in reality it is a Laing pump which is the standard for most proper water cooling projects and is fairly expensive ( the retail version is about £60). I am replacing the seals on mine and going to see if it does the business.

From testing, the usual black Apple wiring to the pump plug is a six pin connector with 2 blanks. When looking at the connector to the pump end on, the pins are like this:

1, blank, 2, blank, 3 , 4.

The connections are as follows: 1 = ground, 2 = V mot (variable), 3 = Tach output, 4 = 12v motor.

To test, connect 1 to ground and 2 and 4 to 12 v. If testing dry then only run for a second as the pump uses the coolant to lubricate itself.

The failure mode of these pumps is the O-ring seal which costs £1.20 to replace. Failure can also be due to burn out of the PCB (fortunately this is not the case for mine), but there is a guy on eBAy who occasionally sells new PCBs that he makes from new surface mount components.

I'll let you know how I get on.

Oh yes and one other thing I have NEVER seen before. This G5 still had the little grey rivet in place in the processor cover. I managed to extract it without breaking it and have saved it. It's a silly little thing but finding one that has not been broken at some point is about as rare as finding a hen with teeth.

 

[MacTester57]

Hi,

This is going to be a slow burning thread, so patience required (!), but I thought it might be of interest and worth a post or two.

Recently I got hold of two defective G5 2.7GHZ dual machines. From these two I actually got one working really well and have overhauled for sale. The other though is dreadful.....a nice case (well, that's what I bought them for really) but a cooling system malfunction took out the power supply big style.

The thing is though having only seen air cooled Mac.s I was really interested by the lovely looking water cooler in both machines. The working one I re-furbished, but on the spares machine I decided that the water cooler is too good to throw away. It has a brilliant little 140 mm aluminium radiator that looks bullet proof (pic attached). It also has an interesting pump. The pump is labelled Delphi, but in reality it is a Laing pump which is the standard for most proper water cooling projects and is fairly expensive ( the retail version is about £60). I am replacing the seals on mine and going to see if it does the business.

From testing, the usual black Apple wiring to the pump plug is a six pin connector with 2 blanks. When looking at the connector to the pump end on, the pins are like this:

1, blank, 2, blank, 3 , 4.

The connections are as follows: 1 = ground, 2 = V mot (variable), 3 = Tach output, 4 = 12v motor.

To test, connect 1 to ground and 2 and 4 to 12 v. If testing dry then only run for a second as the pump uses the coolant to lubricate itself.

The failure mode of these pumps is the O-ring seal which costs £1.20 to replace.

I'll let you know how I get on.

Oh yes and one other thing I have NEVER seen before. This G5 still had the little grey rivet in place in the processor cover. I managed to extract it without breaking it and have saved it. It's a silly little thing but finding one that has not been broken at some point is about as rare as finding a hen with teeth.

Sounds interesting!

 

[Solidww]

Bump and following!

 

[samisnake]

posting to subscribe

 

[chaosdesigns]

I pulled one of these babies when doing my second G5 Mod. I gave it to my son who re-purposed it to cool his PC. With respect to the G5 implementation, what I didn't like about it was that the two heatsinks were plumbed in series, which meant that one CPU was cooled with the heated coolant of the other CPU. Not an ideal design, in my opinion.

 

[Jeffinslaw]

I pulled one of these babies when doing my second G5 Mod. I gave it to my son who re-purposed it to cool his PC. With respect to the G5 implementation, what I didn't like about it was that the two heatsinks were plumbed in series, which meant that one CPU was cooled with the heated coolant of the other CPU. Not an ideal design, in my opinion.

From what I've read, it typically doesn't matter due to how quickly the water is moving through the loop. It still is not the best way but when you're water cooling a 2P system, you aren't going to slap a radiator in between the processors because it doesn't look good and it doesn't really provide much benefit.

Jeffinslaw

 

[chaosdesigns]

I would think a Y connector on either side of the processors might have been a better design.

Oh, and it was interesting messing with the pump and the radiator.... we ran the pump alone with a tube in a bucket of water and it delivered quite a significant stream, but when we hooked up the rad, the stream turned into a trickle. It seems the rad offers quite a bit of resistance.

 

[Solidww]

Now, that is an interesting point. Bummer on the Radiator resistance.
From the reading so far it seems like Apple did use High end water cooling parts? Or am I mistaken?

 

[neilhart]

Hey this will be interesting...

minihack - the last G5 PM that I purchased (and set aside for later) had one of those coolers.

And I put it up on my collector item shelf with the thought that I might find a use for it sometime. So I will follow your slow roll project with interest.

neil

 

[minihack]

Thanks for all the comments so far....and the project hasn't even really begun so far.

I'm not so sure about the radiator resistance point. That may have been a radiator that had got clogged up as the one I have seems fine. We shall see.

I think the first thing after taking down one of this systems definitely needs to be draining what is left of the fluid, pulling apart what can be pulled apart and flushing. The stuff Apple used in their loop was extremely corrosive when exposed to air. The case of the power supply that got leaked onto speaks volumes for that. Mine was almost eaten away by the fluid and resultant rust. Thankfully though the aluminium of the case wasn't affected, just the steel of the PSU and the cover plate.

My idea at the moment is to use the system for a Mini-ITX implementation. I'll try it out first on my older 775 based Zotac board just so I can compare performance and, if anything goes wrong, it won't be too expensive (!).

Apple didn't have a reservoir on their systems, but I'm going to definitely build one in. I have a small pump top res. ordered to fit onto the Laing pump so that'll be here soon.

As for the point about a single pump cooling twin CPUs, well that obviously isn't going to be an issue on any of our systems I'm glad to say.

However, I can say that when these systems are well maintained they do still seem to work quite well. The one in the "good" Mac of the two I purchased is doing a very nice job and doesn't seem to have any significant difference in cooling between the two processors. It also Geekbenches well for the model at 2394 (I know it doesn't sound much, but the usual GB score for this model is 2259).

Will post more when I have a cooling loop to run!