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

Filling the LCS with a vacuum method is the way to go.

At the factory, the system is drawn down to a nearly 0 ATM via the charge port, then liquid filled via the same port.

For the hobbyist looking to duplicate this, you could insert a couple of valved T-fittings into the system, one to draw a vacuum, the other to introduce liquid.

Don't both with Home Depot for tubing, fittings or clamps, try a couple of online mail order sources;

usplastic.com or mcmaster.com

have fun ...

I intend to try the vacuum method the next time I reassemble mine. I plan to use a brake bleed kit. I use the method described by Londonmacuser the first time. it works, but is tedious and I wasn't able to get the last bit of air out. My hypothesis is that surface tension prevented the last bubble from passing out through the relatively small port at the top of the radiator, which is what I was using to bleed. I did not try running the pump or using an external pump. Both sound like interesting, but potentially "wet" ideas. I am looking forward to pictures showing how this idea would work. I will post pictures of my brake bleeder set up once I get a solution to the replacement of my cooling blocks.

Jon

I look forward to seeing the pictures Jon, I have found the pump alternative "wet". In the end I had great success once I tapped the bleed hole with a screw this seemed to mitigate the surface tension issue you correctly identified.

If you have some success with the vacuum method I may try it on one of the loops in my system as it still has some problem with cooling.

Thanks to KoolG4 the mysterious poster with the inside track on these systems I wish I knew at the outset what I do now.

I now believe that I have found a solution for my clogged cooling block, although it required slight modification of the aluminum plates that mount to the CPU daughter board and to the remainder of the cooling system. The Thermaltake WB200 cooling block will fit using the bracket that comes in the kit, but only if you cut off the small "ears" on the aluminum mounting plates that extend over the lateral edges of the CPU. The inlet and outlet barbs on the block are vertical with respect to the CPU, rather than horizontal, and use non-standard threads to mount into the block. My present plan is to eliminate the S-tubes, use extra tubing and perhaps a few L's to make the tubing connections. It isn't going to look pretty, but I am hopeful. I'm not going to be able to get back to this project for a few weeks, but then I'm hoping to run a test comparing the performance of the Thermaltake block to my remaining good original block.

Londonmacuser, are your cleaned-out blocks continuing to perform well?

Jon

Hi Jon

I am struggling to decide what is going on in my case, there are several different factors creating uncertainty.

I swapped the thermal blocks to try and see whether they were causing the problem. The problem has followed the block but is not as serious as it was in terms of it's effect on the fans although the thermal disparity is the same.

This all points to a fault with the block, problem is I'm not sure if I swapped the procs as well, and I will never know as my labelling system failed and I've no pics to fall back on. So the problem may have followed the procs not the blocks or both.

Further complicated by the fact that the loop with the fault has less water in so could be pumping less volume and cooling less, so I'm not sure how much of a fix I have except that I can now run the quad with low fan noise in reduced mode. Overall I'm happy because I want to wait to replace with a Mac Pro.

I would guess that your new solution would work fine. I wish I had got the potential for proc problems out of the loop but my quad still fails thermal calibration even on the proc with no problems. I might like to try your solution at some point because the system seems more flexible to me now I've got it back together and 'working'. Plus adding some of the valves that KoolG4 described would be great for vacuum filling.

Hi all,

Well I just bought a G5 Dual 2.5 yesterday (knowing it didn't work) and discovered that water leaked into the PSU and fried it. After finding this post I dont feel too bad as the leak was very small in comparison to some I've seen here. So I decided to go ahead and re-build the cooling system. I removed the plates that sit on top of the CPUs and quite a bit of fluid freely came out, leading me to assume the pipes aren't clogged. I'm going to replace them with clear tubing so I can see the coolant to make sure it is flowing. Well anyway, I am going to start taking pictures and will post any challenges that come my way and let you know if I am successful (I would call a Dual G5 2.5 for ~300 quite a success 🙂 )I just hope the mobo isn't fried 😐

Thanks for all the help I have found on this forum. I would definitely not have had the courage to do this on my own without the help.

Hey there,
My Power Mac G5's LCU leaked, but, luckily, did not damage the CPU, power supply, or motherboard. Now I am attempting to remove the faulty LCU so that I can replace it or something. I unscrewed the heat sink cover (that small silver plate that says "G5"), and unscrewed two of the screws holding the LCU to the motherboard, but I can't find the rest of the screws and the LCU won't even budge yet. Has anyone else successfully removed the LCU and/or processor from their machine? I'm lost here and I can't find any kind of guide or helpful thread on the internet.

I have a pic of my mobo with the cpus removed, but i cant figure out how to send a picture... so if you send me your e-mail i can send it to you

also, i found a new OEM water pump on e-bay for $35.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270411223130

Thanks! <Edited by Host>
I'm a little leery about buying any parts that weren't specifically designed for the Power Mac G5. I'll only buy a new LCU or fan if I know for certain that it will fit and work inside my machine.

Message was edited by: Hadye

It's worth getting the apple service manual for your model. Taking the CPU out is quite straightforward once you've done it a few times, with the quad model you need 2 long reach Allen keys or the whole process is a nightmare. From memory with the quad there are four bolts that connect the power, 6 that connect the lcu to the board and 4 that secure the proc to the lcu and four captive that secure the lcu. It's tight too.

Mark,

Did you find the pump pinout information earlier in the thread? If you go to my previous thread, which has a link to my project pictures, you can view my pictures of the setup used. I found out that input wasn't needed with 12V pin, and all I needed was 12V to the variable input and then connect the common ground.

So far I've been using the system for about a month now. When starting Celestia 1.6, CPU B will usually spike to 80C, but by then the fans are going well. I compiled source with it for 12 hours straight with no issues using job control with GNU make. It is doing pretty well. With the power save feature automatic on the CPU, the system will hang out at 40-45C both CPUA and CPUB.

Since I used arctic silver 5 compound, I let it run a while, then I re-calibrated the system. I kept getting tafs out of range issues with CPUB. That CPU is always higher under load than CPUA. So I got my room down to 20C and did the test about 3 times and it worked the last time. I think the manual states 25C or so with the thermal calibration document.

I should probably check for leaks soon. Two spare blocks I have from another LCS unit, and they looked to be in better condition than the blocks I am using now. I may swap it out in the future, as I have to repair the mounts that hold the LCS unit to the case. They twist from the case too easily. I'm going to use JB Weld on the broken ones, and put some around the studs that still are attached.

As far as dangerden talk, if someone sends them a spare block, was there any input if they could start something for us folks to use without modifications? I wonder if dangerden would have issues with the manufacturer of the original blocks.

It is so nice to be able to use the machine again, and thank you to the people who provided information to this thread. Hopefully, my input has helped others, as well.

Sincerely,

William

Darn! I wish my APPLE CARE for my Quad hadn't run out or I would have tried getting a new Mac Pro. However I am very happy with my iMac. Still its to bad alot of quads went before there usefull life had passed.

Bill
I found the pics, a close up of the plug connection would be better for my sake. Thanks for that post btw very helpful!
Would a car battery work? I don't have access to a 12v AC to DC converter.
How much artic silver5 did you use?
Temps seem ok. The issue still is the fans kicking on and off under load, not bad just annoying.
Was thinking of getting the sidewinder tubing(you used) and adding a "t" for a fill tube(and fill port). to let bubbles out. Where can I purchase a new mat(the one under the cooling system)? or can we make our own from something cheaper?
regards
Mark

I have the Quad Core 10/2005, Double Delphi LCU. Core A Runs around 30 degrees (F), B runs around 80+ (F). I see no leaks at all. Barely any dust. All the connections look good. The mat is dusty and a little loose, but I see no coolant.

I need specific instructions on removing the unit, checking, rebuilding if necessary and replacing with Thermal Calibration.

QUESTION: Is it possible that a defective sensor is misreading Core B and causing a Thermal Shutdown? Are there thermal sensors on the unit to begin with? If so, is replacement and repair possible, and who sells the parts and instructions?

I hope to refurbish this G5 because it is fast and fun. When it's not crashing.

Best,
Doctor Ken
9/25/09