PowerMac G5 Quad: An attempt to replace the waterpump

Discussion in 'PowerPC Macs' started by fernkorn, May 18, 2009.

  1. fernkorn macrumors newbie

    May 18, 2009

    in 2006 I bought a PowerMac G5 Quad (Costs: About 3500 $). Now in 2009, I suddenly experienced severe problems using the machine. When I turned it on, after 4-5 minutes the OVERTEMP LED came up and 2-3 minutes later the whole computer would go nuts and crash.
    After endless calls with Apple "Care" (funniest thing I've ever experienced. They wanted me to pay 1500 USD to get a replacement kit. Sorry, but they seem to be nuts - I could have bought a whole new quad or even a used Mac Pro for that money) I decided to disamble the quad myself.
    It really takes some time to disamble this CPU beast, you just have to loosen about a zillion screws to get it out of its cage.
    After several tests without luck I noticed that the CPU B cores get really hot in IDLE Mode (about 85°C). When the complete disambly of the CPU Unit didn't bring any luck, I decided to completly remove the unit. And guess what? Overtemp LED was gone - everything worked fine again. Now I have a Dual G5 2.5 GHz.
    Before I removed CPU B, I touched the radiator i noticed that the lower end of it (where CPU Core B is located) isn't even handwarm, while the top end is really hot. (I think those are two separated circuits).
    My conclusion: The cooling pump of CPU B bit the dust. No circulation equals very hot CPU equals OVERTEMP equals LED806 Checkstop (CPU hang)

    As I don't want to pay 1500 USD for a thing that may cost about 20 $ in production, I tried to find that pump on the Internet. And guess what? Success!
    I found this pump that looks very similiar to that on the quad: http://www.laing.de/produkte/pumpen/gleichstrompumpen_ddc/ (Sorry, the page is in German - I'm from Austria)
    I think I'll give this thing a try, since it costs about 70 euros which is A LOT cheaper than a new CPU Unit or even a Mac Pro.

    My questions is now: Has anybody ever done such a repair? I know it won't be easy, but i think it would be nice if my quad could be back to full power.

    Does anybody know what cooling liquid Apple is using? I think during the repair I won't be able to recover all of the liquid, so I may be forced to refill the unit.

    Is the radiator divided into two sections or is there only one? (Two or one circuits?)

    Thanks, I'll let you know if I make any progress by updating this thread.
  2. fernkorn thread starter macrumors newbie

    May 18, 2009
    Thank you _very_ much.

    Seems that I'm not the only one who's experiencing severe problems with his Quad Cooling system. In a matter of fact, Apple's liquid cooling system just sucks. Damn, I'm really pissed - I didn't buy a 3500 $ system just to get it rendered useless after 3 years. Funny but true: My 1800 $, five year old Dual G5 2.0 GHz is running just like I had bought it yesterday.

    Although it would be very challenging to replace that defective pump, after reading that Apple Discussion thread, I think I'll throw that thing as defective on ebay and get a Mac Mini.
  3. 300D macrumors 65816


    May 2, 2009
    How did you remove a CPU without the fans going full blast or having a calibration CD to fix it?

    How about getting air heatsinks from a dual 2.3, adding a fan or two and ditching the whole water system? If a quad G5 didn't cost as much as a quad MacPro, I'd consider trying that myself.
  4. fernkorn thread starter macrumors newbie

    May 18, 2009
    I have the apropriate Apple Service CD for my system. I reran the Thermal Calibration after I removed one of the CPUs. However, the system crashed while recalibration. (OVERTEMP, Checkstop) Don't know why, but I think cause it's looking for second CPU or something. Or - and that's what I think - the Apple Service Application is just a bunch of crappy software.

    Good idea, however, I don't think the dual 2.3 heatsink will fit on those quads. Each core has a massive heatpipe leading to a huge heatspreader attached to it. Don't think this going to work unless I could completely remove the two cpu cards and reattach a genuine 2.3 heatsink. I'll check the Apple Service Manual. Thanks for the input.

    Edit: I forgot. All the new PCIe Duals have only one cpu (two cores). The quad has two CPUs (Two connectors on the Logic Board). I'll have to look for a Dual 2.3 cooler which were installed in the old skool dual systems. (two cpus, one core)
  5. 300D macrumors 65816


    May 2, 2009
    That was the idea.
  6. fernkorn thread starter macrumors newbie

    May 18, 2009
    OK, I see...

    Hmm, do you know if it's possible to do that? From what I've seen those CPU cards look pretty the same on every G5. Even the mounting holes seem to fit.
    Even if it's possible - won't the 2,5 GHz Dual Core Dies produce to much heat? I've got a notion that Apple didn't design those watercoolers just for fun.
  7. 300D macrumors 65816


    May 2, 2009
    That could be a problem. IBM never actually released a G5 CPU faster than 2.0ghz so all Apple's machines higher than that are overclocked.

    Worst case, you can make your own cooling system using common CPU modder parts with the stock heatsink as a base. There is no rule saying you must use OEM Apple or functionally identical parts.
  8. zmttoxics macrumors 65816


    May 20, 2008
    Not true. IBM produced all of those CPUs with those speeds stock. IBM still produces the 970MP 2.5 duals found in the Quad 2.5 can you find them in the Fixstars PowerStation. IBM doesn't use them in their servers anymore, they have been replaced with the POWER6 series which have clock rates well in the 5ghz range and 6ghz planned by the end of the year. To put it into perspective, the TDP of the 970MP was 75watts, the TDP of my desktop AMD CPU (quad core 9950 2.6ghz) is 125watts - a much hotter cpu running on Air Cooling. The water cooling was strictly an Apple design fail.
  9. fernkorn thread starter macrumors newbie

    May 18, 2009

    Hmm, so you mean it should be possible to run the G5 Quad just by using a "standard" air cooling? As I said before, I do own a G5 2.0 GHz which is cooled by air. (Massive heatsinks)

    The idle temperatures are between 60 - 70 °C. From my point of view, the 2.5 Ghz Dual Core should produce A LOT of more heat.
    Altough the liquid cooling was a design fail, I think, Apple had done the right thing to keep this thing cool without risking the fans would go full blast for 90% of the time someone is using this kind of PowerMac.

    Anyway, I don't care if the fans sound like F16 turbine. I just want that system to be stable. My quad is used as a server - kept in a room which has been built for an atomic assault. (Yeah you know, cold war, Austria's closeness to Russia - so every building constructed in the mid 80's has such a room - forced by law)

    So do you think it'd be possible?
  10. zmttoxics macrumors 65816


    May 20, 2008
  11. AlexMaximus macrumors 6502a


    Aug 15, 2006
    A400M Base
    I would give it a try...no doubt !!!

    I want to mention that there are software utilities and programs available where you can slow down your processor, for example from a dual 2,5 gig to a 2,3 gig or even slower.
    Traditionally this tool is used on laptops to conserve power when you don't need the full processor speed during simple tasks. There might be a big chance to use that and have no problem with the heat sink from the late Powermac 2,3 dual.
  12. muller macrumors newbie

    Aug 5, 2009
    G5 2.3/2.5 Quad (late 2005) Service Source

    Have you G5 2.3/2.5 Quad (late 2005) Service Source? (28MB Pdf file)
    Can you send me?
    MNY TKS in ADV
  13. mkaake macrumors 65816

    Apr 10, 2003
    As someone who just had his G5 offered a warranty exception (and they ended up giving me a new Mac Pro, but that's *very* rare), I'd recommend that you call Apple care back up. It needs to be classified as a health and safety issue to get to the level 2 specialist, who will then get a hold of a product engineer to ask about getting a warranty exception.

    1st level - explain that you have a health and safety issue, and need to speak with a level 2 specialist, explaining that you have coolant leaking inside of the case (and as such, you don't need to take it to an apple store to find out what the issue is - it's very obvious). If they give you hassle, hang up, and call back to get a hold of another tech. Mine was very supportive, and I explained that I heard under some circumstances, they were providing warranty exceptions... it took about 30 minutes for them to get the ball rolling.

    2nd level - asks a few questions about how it happened (what you noticed, etc.), and then goes through a list of 10-12 canned questions he's required to ask. he will then say that he's going to contact engineering to find out what they would like to do with your machine.

    3rd level - they call you back (up to 3 days later), and let you know that they've decided to repair your mac free of charge, because this is a pretty serious issue (verbiage may change from time to time). They'll offer to set up an appointment with you over the phone at your local apple store (you can set it up yourself, just make note of your case number).

    At this point, you can take it in to any apple store for a free fix-up. I haven't heard of anyone trying this in the last few months who's been rejected... just need to push past the first level of customer care (mine was 1500 days out of warranty when I made the call...).

    Good luck!
  14. AZREOSpecialist macrumors 68020


    Mar 15, 2009
    Email Steve Jobs

    My liquid cooling system leaked about two years ago. Cost of repair: $1,400. I emailed Steve Jobs about my issues, got a call from Jobs' executive office and they paid for the repair.

    I don't have his email address anymore, but you can probably find it in one of these forums or on google. It's worth a shot.
  15. goodcow macrumors 6502a

    Aug 4, 2007
    It's sjobs@apple.com - Apple Executive Customer Service replaced my MacBook Pro with a higher spec model after about a dozen repairs which made me send an E-Mail to them.
  16. gugucom macrumors 68020


    May 21, 2009
    Munich, Germany
    If the warranty exception don't work that could be the right thing to do. Apple applied the liquid system only to the 2.7 GHZ PPC970FX and the 2.5 PPC970MP. Both CPUs are of the same 90 nm manufacturing width but the MP has twice the cores (dual core). I would think that the 2004 DP 2.3 GHz PPC970FX heat sinks would be a fit if you detune the Quad to 2.3 GHz. It is either that or using fanned heat sinks from other apps of that CPU range.
  17. OllyW Moderator


    Staff Member

    Oct 11, 2005
    The Black Country, England

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