Heikki Lindholm

Q: Working on the G5 quad liquid cooling system

I have a G5 quad with the one pump Delphi LCS ("version 1"). I'm guessing the LCS is clogged because when the machine sits idle (even in reduced CPU setting, which cuts the GHz in half), the fans and the pump slowly, over several hours, go to full speed. Temperatures of CPU B, particularly the second core, shoot to near 100C when loading the CPUs. ASD 2.6.3 usually passes, but sometimes ends in checkstop and overtemp. A local mac service center, which I had the machine checked at (in hopes of getting free repairs because of a leak), said it's fine.

 

As a simple first measure, I tried replacing the thermal paste on the CPUs, with little effect. The LCS didn't seem to be leaking or corroded anywhere, but when handling it, it sometimes made a bubbling noise, so, there's probably air in there. I thought I'd take the LCS apart next, but before that I have some questions which I hope someone can answer.

 

Which one, the upper or lower, is CPU A and which is B? I've read the machine runs on one CPU just fine, but which one?

 

If I switch the CPUs the other way around and later switch back, does something in the nvram reset so that thermal calibration needs to be run? I'd rather not run it as it seems to have mixed success.

 

What material/size are the CPU block O-rings on this system?

 

If I use a vacuum pump on the service valve (I gather it's of the "r134a high" type(?)), what would be a safe level of vacuum? Has anyone tried using the manual brake kits, or car cooling system refill kits that use compressed air and venturi valves, on the LCS?

 

I suppose I'm just going to try attaching a hose as a reservoir to the service valve and fill through that first, but if that doesn't bring satisfactory results, I'll level-up to some sort of vacuum method.

PowerMac

Posted on Sep 17, 2011 11:59 PM

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Q: Working on the G5 quad liquid cooling system

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  • by G5Lover,

    G5Lover G5Lover Jun 10, 2013 10:31 PM in response to Ramón G Castañeda
    Level 1 (0 points)
    Jun 10, 2013 10:31 PM in response to Ramón G Castañeda

    Sorry, I mean YES I'm in Tiger.

  • by G5Lover,

    G5Lover G5Lover Jun 10, 2013 10:39 PM in response to Ramón G Castañeda
    Level 1 (0 points)
    Jun 10, 2013 10:39 PM in response to Ramón G Castañeda

    Ramón,

     

    let me know what you had the Processor Performance set at when you get there. If it was set at "Highest," that might explain the slightly high idle temps you reported earlier.

  • by Ramón G Castañeda,

    Ramón G Castañeda Ramón G Castañeda Jun 10, 2013 10:44 PM in response to G5Lover
    Level 4 (1,468 points)
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    Jun 10, 2013 10:44 PM in response to G5Lover

    Thank you for the clarification. 

     

    Totally forgot about the Energy Saver preferences, as I normally only access them for setting up a computer for the very first time and never revisit them.

     

    I'll try switching Performance from Highest to Automatic and see what happens with the temperature readings after a good while.  Fortunately Hardware Monitor keeps a historical curve of the readings.

  • by Ramón G Castañeda,

    Ramón G Castañeda Ramón G Castañeda Jun 10, 2013 10:43 PM in response to G5Lover
    Level 4 (1,468 points)
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    Jun 10, 2013 10:43 PM in response to G5Lover

    G5Lover wrote:

     

    Ramón,

     

    let me know what you had the Processor Performance set at when you get there. If it was set at "Highest," that might explain the slightly high idle temps you reported earlier.

     

     

    Yup.  It had been set at Highest from day one.  I just changed that.  Thank you.

  • by G5Lover,

    G5Lover G5Lover Jun 10, 2013 10:51 PM in response to Ramón G Castañeda
    Level 1 (0 points)
    Jun 10, 2013 10:51 PM in response to Ramón G Castañeda

    Ramón G Castañeda wrote:

     

    Thank you for the clarification. 

     

    Fortunately Hardware Monitor keeps a historical curve of the readings.

     

    Ramón

     

    Where did you get Hardware Monitor? Did it come bundled with something? I really like all the different monitor readings you show in your screen shots. I have iStat Pro widget and Temp Monitor program and both of them have software glitches. They also don't show enough settings for my liking.

  • by Ramón G Castañeda,

    Ramón G Castañeda Ramón G Castañeda Jun 10, 2013 11:10 PM in response to G5Lover
    Level 4 (1,468 points)
    Desktops
    Jun 10, 2013 11:10 PM in response to G5Lover

    No, it wasn't a freebie.  I bought it directly from the developer, "Marcel Bresink Software-Systeme":

     

    http://www.bresink.com/osx/HardwareMonitor.html

     

    screenshots at:

    http://www.bresink.com/osx/216202/screenshots.html

  • by Ramón G Castañeda,

    Ramón G Castañeda Ramón G Castañeda Jun 11, 2013 12:37 AM in response to G5Lover
    Level 4 (1,468 points)
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    Jun 11, 2013 12:37 AM in response to G5Lover

    TEST.

     

    My posts are disappearing.

  • by G5Lover,

    G5Lover G5Lover Jun 11, 2013 10:24 AM in response to Ramón G Castañeda
    Level 1 (0 points)
    Jun 11, 2013 10:24 AM in response to Ramón G Castañeda

    Ramón G Castañeda wrote:

     

    TEST.

     

    My posts are disappearing.

    Ramón,

    Looks like your posts came back in force . I had the same thing happen last night when I finished a post and clicked the "Add Reply" butoon, the site choaked on it and said there was some kind of error. The site probably was down during that time. Before you reposted the links for me to Hardware Monitor, I actually had done a search and found it. But thanks.

  • by Ramón G Castañeda,

    Ramón G Castañeda Ramón G Castañeda Jun 11, 2013 7:07 PM in response to G5Lover
    Level 4 (1,468 points)
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    Jun 11, 2013 7:07 PM in response to G5Lover

    G5Lover wrote:

     

    Ramón G Castañeda wrote:

     

    TEST.

     

    My posts are disappearing.

    Ramón,

    Looks like your posts came back in force

     

    Whoa!    I hope the moderators can delete the multiple postings. 

     

    Yes, it was server error.  As a matter of fact I hadn't been able to see any posts after the one where you asked about where I got Hardware Monitor until seconds ago, despite my trying a gazillion times last night and again today; not even yours from this morning.  Bummer! 

  • by Ramón G Castañeda,

    Ramón G Castañeda Ramón G Castañeda Jun 11, 2013 7:27 PM in response to G5Lover
    Level 4 (1,468 points)
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    Jun 11, 2013 7:27 PM in response to G5Lover

       More weirdness:

     

    When logged in to reply, I can reply but then I cannot see any messages after the one quoted below.  Not even the ones I just posted.

     

    But when I SIGN OUT, I can see all of them.  This is repeatable at while, and happens both with Firefox and with Safari.

     

    LAST MESSAGE I see in this thread when SIGNED IN is this one I'm replying to:

    Re: Working on the G5 quad liquid cooling system

       Jun 10, 2013 10:51 PM    (in response to Ramón G Castañeda)

     

     

    G5Lover wrote:

     

    Ramón G Castañeda wrote:

     

    Thank you for the clarification. 

     

    Fortunately Hardware Monitor keeps a historical curve of the readings.

     

    Ramón

     

    Where did you get Hardware Monitor? Did it come bundled with something? I really like all the different monitor readings you show in your screen shots. I have iStat Pro widget and Temp Monitor program and both of them have software glitches. They also don't show enough settings for my liking.

  • by nospoonzz,

    nospoonzz nospoonzz Jun 11, 2013 7:44 PM in response to G5Lover
    Level 1 (0 points)
    Jun 11, 2013 7:44 PM in response to G5Lover

    This is where the "T" fitting is. As far as the coolant. I have seen the pink stuff always, always cause corrosion,build up on anything it touches if left without maintenance. A lot of import cars use it. Apple used it and my system was very clogged. Always see good things with Dexcool.

  • by nospoonzz,

    nospoonzz nospoonzz Jun 11, 2013 7:45 PM in response to nospoonzz
    Level 1 (0 points)
    Jun 11, 2013 7:45 PM in response to nospoonzz

    forgot the pic. sorry.IMG_0057.JPG

  • by G5Lover,

    G5Lover G5Lover Jun 12, 2013 10:04 AM in response to nospoonzz
    Level 1 (0 points)
    Jun 12, 2013 10:04 AM in response to nospoonzz

    nospoonzz,

    Thanks for the pic.  I kinda figured you must have put the "T" on the return since you replaced the aluminum return pipes with hoses.

     

    The pink coolant was what came out of mine also. I only flushed the "B" side cooling circuit of my LCS, since the "A" side was not overheating at all. I opted to not invade my entire LCS original pipeing unless necessary.

     

    Turns out I got lucky at my guess and only the "B" overheating side needed flushing. Of course the "A" side that still containes the original Apple coolant mix will sooner or later need flushing. Probably sooner! But now I am comfortable with my proceedure, so it should be pretty straightforward for me.

  • by G5Lover,

    G5Lover G5Lover Jun 12, 2013 10:13 AM in response to Ramón G Castañeda
    Level 1 (0 points)
    Jun 12, 2013 10:13 AM in response to Ramón G Castañeda

    Ramón G Castañeda wrote:

     

       More weirdness:

     

    When logged in to reply, I can reply but then I cannot see any messages after the one quoted below.  Not even the ones I just posted.

     

    But when I SIGN OUT, I can see all of them.  This is repeatable at while, and happens both with Firefox and with Safari.

     

    Ramón,

     

    That's why when posting on forums I rarely type my post while logged in. Many times the forum host's server has a log in time limit and if you take too long it loses you by the time you end up actually posting or the server goes down and loses you.

     

    I type my posts off-line in a text doc. then go on-line and post them quickly.

  • by G5Lover,

    G5Lover G5Lover Jun 12, 2013 11:17 AM in response to Heikki Lindholm
    Level 1 (0 points)
    Jun 12, 2013 11:17 AM in response to Heikki Lindholm

    My "Post" LCS flush-'N-fill Temps & Fan Speeds under a load…

    Thought I'd show some temps and fan speeds during some intense rendering and encoding processes in iDVD when I'm burning a movie to a DVD. These temps and fan speeds are pretty much constant during the processing. There were a few high spikes where the temp on the #2 diode of the "B" core rose only as high as 153º and only for a few seconds. I notice that during this process of video rendering the "B" cores seem to remain 10º to 20º warmer than the "A" cores. I'm thinking that the "B" cores are being sent slightly more tasks than the "A"s. At idle there is only a two to three degree difference between any of the four processors.

    LoadTemps.png

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