Quad G5 Liquid Cooling Pump Chugging, nasty thermal disparity between cpu's

I am also confused. I found a patent application filed in 2004 by Cooligy, the company whose name appears on the LCS, with drawings showing a cooling block that bears a strong resemblance to the blocks in our Quads. It does have a complex set of passages close to the surface to be cooled and even says that there is a copper "foam" in the passages closest to the surface to be cooled. You can find the patent at www.uspto.gov and searching for the publication number 20050269061.

If your cooling blocks appear to have similar resistance, but you have a large temp disparity between your CPUs, then I agree with your conclusion that a pump is at fault. I never really measured the performance of my pumps. Without the resistance of the cooling blocks, they pump lots of volume in a short period.

I am going to remove my second CPU and the associated cooling components this weekend. I'll let you know if, as I suspect, the resistance of that cooling block has significantly increased.

Yesterday, I noted an almost 30 C difference in CPU temps under light processing load. I disassembled the cooling system this morning and found that the cooling block corresponding to the hotter CPU was nearly impossible to blow air through. The other cooling block was somewhat restricted, but much less so.

I am in the process of cleaning the cooling blocks by introducing a phosphoric acid etch solution into the outlet port of each block. The solution is a commercial product intended to etch metal prior to painting. I am getting a small amount of fine black particles from the inlet port when I drain the solution. I suspect that these cooling blocks will probably not last very long if I re-use them, but without a source of replacement blocks, I may have to do that.

The good news is that the epoxy that I used to re-assemble the cooling system is easier to disassemble that what Apple used originally.

30c is about the difference I had before dismantling, at least you have confirmed that the cooling block is restricted, since the other cause could be thermal overload in the chip itself. I was planning to swap the cooling blocks to check that it's not the chip itself which is overheating (or the temp sensors failing).

Not sure why the acid would do any long term damage, I have been getting some limescale looking flakes out of one of my dry cooling blocks so maybe there is limescale or crystal build up inside. Good to know the epoxy is working though, I'm waiting for the pipes and coolant to arrive will be refilling and testing this week.

Hello everyone.

In May, my dual G5 decided to not turn on. So I took the cover off and removed the plastic cover and attempted to turn it on and I had sparks and smoke. Apparently the water blocks leaked and corroded the circuits on the board and caused a nice low resistant path which made some nice magic smoke!

Now that I have a bit of money to fix it, I have some replacement CPUs, and some liquid cooling supplies on the way. I did not find any gunk in the system when I flushed it. This is a Dual G5 Late 2004 model with the Delphi cooling system and one pump. Here are some pictures of the removed pump:
http://cross-lfs.org/~kb0iic/DualG5/ The 1024 pictures are scaled down for people who don't want to load the large pictures.

I did not really see signs of fluid leaking from the pump, but I cannot rule that out as the Liquid Cooling System had been sitting for a while. However, there was massive corrosion on the water blocks at the edges where the two pieces meet to seal the water block. Also, there wasn't much crud on the cooling block's copper fins where the water passes through, so I removed what I could and have let it dry.

When putting the pump and water blocks back together, would anyone suggest RTV gasket sealer, or just silicone on the o-rings, or just use Loctite like the french site has, which was posted earlier?

Currently I'm planning on using clear tubing, some Fesser One clear/blue coolant, and some screw down clamps. For filling I suppose I can use either an r134a filler adapter and some hose, or an inkjet syringe. Anyone have some ideas of the best way to bleed the system, or any type of method? I've been looking already in the PC liquid cooling forums and am wanting some more ideas from experienced users here.

Sincerely,
William

Berzerkula,

The next time I reassemble my Late 2005 Quad G5 LCS I am going to try using a brake bleed kit (intended for use when rebuilding car brakes) to get the last of the air out of the system. I'll post some pictures when I try it. First, I have to find some replacement water blocks, as mine are internally corroded and I am not hopeful that I can clean them adequately. The blocks on this version of the G5 LCS cannot be disassembled for cleaning, as they are soldered or brazed.

The first time a
I re-assembled my system I used a Loctite 5-minute epoxy to seal various points of possible leaks. During the few hours of operation, I had no leaks. I was also able to disassemble the system without too much trouble. You can find a link to this epoxy a few posts up from this one.

Londonmacuser,

I have found two water blocks intended to cool Northbridge chipsets for Intel/AMD motherboards that I think can be used to replace our blocks. They are the Swiftech MCW30 and the DangerDen MPC_Universal. Use of either will require mods to the mounting scheme that Apple designed. That is, the blocks will be hard-mounted to the CPU daughter-board rather soft-mounted by means of that "four-legged stool" contraption. They will also require replacement of the vertical tube barbs that come with the blocks with swivel, 90 degree barbs. I have located some that should work from a company named Koolance. I am going to think this through carefully before spending the money to buy the parts, as the clearances are going to be tight. I am also worried that the required mods will mess up the aspects of Apple's design that permits the CPU daughter board to align to the sockets on the main logic board as you mount the whole CPU/LCS system. Have you considered any of these replacement block options?

jpmeyer

Sorry to hear your blocks are terminally corroded. I guess you have few options but try to use some third party alternatives, there must be a few broken units out there gathering dust shame we can't lay our hands on them.

Looking at the two blocks you mentioned it seems the first problem would be routing the pipes from the rad, if the pipe can be bent from the bottom of the rad to the inlet then you could drop the ali pump feed tube and go direct to the pump from the block. Why not keep the four legged piece but drill it so that it holds down the new block i.e. drill two holes for the connectors. Since the daughterboard moves individually from the upper cooling mech it would be difficult to mount rigid pipes on the blocks if they were fixed to the daughterboard but soft pipes could work.

I am not too worried about a small amount of air in the system but the car bleed system sounds useful, were you thinking flexible tube with slit or the more complex system with reserve tank?

I'm thinking about going without the epoxy to start with, it should be watertight anyway. I've also dropped the rubber sleeves on the pump inlet and outlet, not sure how important they are. Looking forward to refilling it this week.

jpmeyer,

Thanks for the input. I'm keeping pictures here and I'm updating the page all the time as I go through this project.

http://berzerkula.no-ip.org/~kb0iic/DualG5/index.html

Click on the large pictures link to view the larger pictures.

Right now I'm letting the system set for about 24 hours so the sealant dries that I used with the pump and water blocks. The r134a high side connector that is on the radiator unscrews and I can fit a 5/8" pipe I got from NAPA auto parts store for cheap over the fill port to fill the radiator. I have a replacement r134a high side adapter because I punched the middle port stopper out of it. I'm just going to do my best to fill it and then get it air free as much as possible. Once that is done, I'll run the system for a while, once I get the right pins hooked up to my power supply, and check for leaks. If all is well, I'll mount the CPUs, use some Tim Consultants T-C 0098 Thermal Compound. I also have Arctic Silver 5, but it is kinda old. Many years old.

So, tomorrow afternoon I will probably begin the great filling of fluid!

-William

Ahoy everybody,

I'm at a standstill. I went to test my pump before filling the system and it seems that my pump as well is pretty darn noisy and isn't working properly. Sometimes it will work, and other times it will not work. So my guess is, the pump stopped working properly, causing the temps to reach up to 90C or so, causing pressure to squeeze liquid through the seals of the water block and onto the processors. Also, I now remember there being fluid underneath the gasket of the diaphragm part of the pump which was on the plastic. So I take it that possibly the pressure being increased when the blocks got hot from the lack of water flow was the final culprit?

I'm going to order another pump. I had a second liquid cooling system arrive, that was used, and its pump is dead, won't even turn on. Poor pumps. Have the people using the Swiftech MCP350 or MCP355 been witnessing positive results with those pumps?

William

Eureka! The system is alive again. The pump was okay, I added coolant and it acted better. The cpu calibration passed on both CPUs. I decided to go ahead and use Arctic Silver 5 for compound. CPU A is at about 48C idle and CPU B is at about 51C idle. So it seems to be tons better than being at around 90C idle.

From now on I'll make sure I check on the system regularly to make sure all is going okay. This has been a fun project, luckily didn't cost so much doing it all myself and finding parts easily.

Don't be afraid to contact me for more information. Kallisti, have you progressed anymore on your repair?

-William

Congratulations.

I've been trying to fill my dual pump system today. I managed to fill one side properly but struggled with the other and generally had a nightmare. Found that it was easier to refill and bleed by hand rather than using the pumps, but now need to get some smaller hoses and I'm struggling to find a way to seal the fill and bleed posts.

Oh well maybe better luck tomorrow for me, still good to see you had some success William.

I filled it up from both ends. The last time I filled it, which seemed better, I broke the loop at the line between the pump output and the radiator. I used a long tube on the pump output and used the tube that goes from the radiator to pump output. I filled both ends with fluid and got as many bubbles as I could by raising the long tube high. Bubbles would come out of the pump output.

I had a plastic container with fluid and I'd raise and lower the long tube I had going to the pump output till the short tube I had on the pump output where at the edge of the tubes, then I'd quickly submerge them. It was hard to do with one hand holding one hose, then the other holding a hose and container. I'd turn the pump on and to get it started sometimes I'd squeeze on the pump output tube till it started going. After the pump start going and the system was full, I would turn the pump off, have a piece of tape ready, and a rag to dry off the hose end I am going to tape. I would keep the long tube to the radiator in the container and lower and raise it till I got fluid in the hose I'm going to tape off right at the end and I'd tape it. That'd seal it.

By this time the tube coming from the radiator which goes to the pump output is ready to be quickly attached. So I removed the long tube from the radiator, and while doing that I close off the pump output with my thumb. I then take off the tape with teeth or thumb or something nearby, then close it off with a thumb, then ya do the quick Indiana Jones move and get it done quick. I did have a very tiny air bubble from when I attached them, but that is no longer in the system during pumping, it's somewhere in there, but I never see it. Hope this helps. I worked hours on filling mine, too.

William

Er I mean, keep the hose you remove from the pump output connected to the radiator output. I used a long hose with the pump output. Lay the system so it is laying on the radiator. Worked well for me. Those of you using systems with two pumps, might have to give your story. I think one was already told.

In my previous post I started getting the long hose confused with the radiator, and it wasn't connected to the radiator. Sorry about that.

-William

Managed to fill the second part of my 2 part system today, quite a lot of lessons learned. Eventually bled well and the usual size bubble remains for the most part out of the way at the top of the radiator. Now on the bench waiting for reassembly.

posted some more pics :-

http://gallery.me.com/mrandyjones/100003

Quite a few lessons learned, not a job I want to do again. You can use an extra pair of hands, and somewhere I have lost 600ml of cooling fluid!

"+From what I can remember the most unreliable system was the Delphi unit with two pumps. After some time Apple started to produce late 2005 G5s with Panasonic units featuring one pump and these seem to be more reliable.+"

Please note that Delphi NEVER produced a cooling unit with (2) pumps. Those 2-pump units were produced by Cooligy to their own design. The "chugging" that was described is most likely a problem with one or both pumps being partly filled with air and not being able to pump liquid as they should. This is not a pump failure, rather, air has been introduced to the system at some point.

Message was edited by: Kool G4

Interesting because the pumps do say Delphi very clearly on the lids. Kool G4 do you know whether Cooligy still exist?

I had another go at mine today and finally I'm back to normal fan levels, this is not an easy job to do and I have lots of experience with computer hardware. All the same I'm running mine in now and if the problem is fixed I'll be very happy. At least so far it's a good outcome if anyone else has the time and energy to invest in their own Quad I would say go for it.

I'll be getting a Mac Pro soon anyhow but I can find some use for the Quad if my plumbing holds up. I hope to find time to write up my experiences/advice about the job but suffice to say it was definitely the cooling system at fault.