PMG5 Oil cooling?

Discussion in 'PowerPC Macs' started by mzs.112000, Jun 10, 2016.

  1. mzs.112000 macrumors regular

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    #1
    Is it possible to cool a PowerMac G5 with veggie oil instead of water? They do it with X86 PC's(not OEM ones), it cools better than water and, if the oil spills, it does not conduct electricity, entire computers have been submerged completely in oil and they still function.
     
  2. tevion5 macrumors 68000

    tevion5

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    #2
    G5 pumps don't use water. They use some kind of convective fluid alright that does cause a lot of corrosion if it leaks.

    How you would go about retro fitting a stock pump with what you are suggesting sounds to me like too much work to be worth it however. Although as out G5's age such harsh measures may one day be necessary.
     
  3. mzs.112000 thread starter macrumors regular

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    #3
    I do not think anything would need to be retrofited, just dump out the stock cooling fluid, and dump oil in, maybe you would need a more powerful pump.
     
  4. MagicBoy macrumors 68040

    MagicBoy

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    #4
    LOL, not the most sensible idea I've heard this week! Stick to proven liquid cooling solutions.

    The only oil cooled computers I'm aware of are project builds submerged in something like a fish tank. Oil is viscous so would need a more powerful pump, it also tends to eat away at plastic and rubber fittings unless they are specially designed for it.
     
  5. mzs.112000 thread starter macrumors regular

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    #5
    So, what would be a very effective way of cooling a quad without the risk of corrosive liquids? I might get one someday but, I want to use it as a main computer(I already know about the age, speed, apps, etc...), and I do not want to risk ruining the whole thing.
     
  6. MagicBoy macrumors 68040

    MagicBoy

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    #6
    I'd use off the shelf PC Coolant additive. It's designed for the purpose...
     
  7. bunnspecial macrumors 603

    bunnspecial

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    #7
    Not sure how it would cool "better"-oils have a lower specific heat than water or a water/ethylene glycol mixture and the higher viscosity would make it more difficult for the pump to move it around. You'd also have to make sure all the seals(including in the pump(s)) are compatible with oil.

    The main uses for oil in cooling are when you have electrical equipment that needs to be submerged in coolant. This is somewhat common on big transformers, and it's usually mineral oil or some sort of PCB laden oil in the old days. Many simply cool by convection. Oil is used because it's effectively non-conductive-they'd likely use water in those applications if it wouldn't cause other issues.

    Engine oil coolers are also common in more performance oriented cars and do help to get rid of some heat but it's nowhere near as much as the main water cooling system. Both my cars have oil coolers, which look like small radiators sitting in front of the main(water) radiator. I cover the one in my MG in the winter because keeping the oil at optimum operating temperature(and keeping the viscosity of the relatively heavy oil as low as possible) is more beneficial than cooling the oil.
    --- Post Merged, Jun 10, 2016 ---
    AFAIK, it's mostly water, although it does have some fluorescein in it that makes it pretty under UV :)

    IMG_2095.jpg

    I wish I'd actually taken the time to analyze this when I had it.
     
  8. abundantmussel macrumors regular

    abundantmussel

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    #8
    I've only ever seen oil cooked solutions in two applications the first was in high performance cars, I briefly owned a Nissan skyline R34 (a sought after car when I started driving thanks to 2fast2furious) which used an oil cooler like Bunn described, I've seen the same in turbo BMW M3s (I have a thing for older BMWs, having owned 7 or 8) a small radiator located in the bumper where the large mesh is located and the other application has been in completely submerged systems, I remember a few years ago roughly around 2010/11 a PC which was over clocked that had to be submerged in a barrel to be cooled. But given my limited chemistry experience (which is limited to my side business of making eliquid for vapers, using propylene glycol and vegetable glycerin, oil is thicker than water so you would need a higher powered pump to move the liquid, any filters in the pump lines would need to accommodate for the thicker viscosity of the oil and also the heat absorption of the liquid. I think that apple used the best they could find at the time circa 2005 to cool the G5 quad and it's brothers the 2.5 and the 2.7, in liquid cooling not much has changed in the last 10 years.
     
  9. MagicBoy macrumors 68040

    MagicBoy

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    #9
    As we know the early G5s used Delphi liquid cooling systems ... and they are an automotive parts supplier. There's multiple reasons internal combustion engines favour water-cooling (with additives added to prevent corrosion and make it more efficient), rather than using more (non lubricating) oil.

    I'm unsure where the OP gets the idea the the factory solution is corrosive. The water component just evaporates and leaves some trace additives behind. It's not like it's using Xenomorph blood. ;)
     
  10. mzs.112000 thread starter macrumors regular

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    #10
    I thought it was corrosive because, early ones would leak coolant, and it would corrode the aluminium that the case is made of.
     
  11. tevion5 macrumors 68000

    tevion5

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    #11
    Damn I thought it literally was. Gonna make using my G5 quad a lot less exciting from now on.
     
  12. 128keaton macrumors 68020

    128keaton

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    #12
    Its not corrosion per se, just residue that can harm things
     
  13. mzs.112000 thread starter macrumors regular

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    #13
    Ah okay.
     
  14. MysticCow macrumors 6502a

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    #14
    Wait, this sounds an awful lot like repurposing a G5 as a deep fryer.
     
  15. bunnspecial macrumors 603

    bunnspecial

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    #15

    Great idea! I have a spare Quad in my office...
     
  16. MagicBoy macrumors 68040

    MagicBoy

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  17. bunnspecial macrumors 603

    bunnspecial

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    #17
    I'm not British. How about some fried chicken? :)
     
  18. oi! Suspended

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    #18
    Oils come in a range of viscosities, from ash felt and maritime grease to diesel, kerosene and racing car brake fluid. most oils you might sensibly choose for such a system are indeed more viscous that water, which means a stronger pump as has been mentioned. Oils can eat away at seals and hoses, again mentioned, but the automotive scene meets these demands. There are hoses that will take oils, there are seals that will too, oil doesn't have as good thermal transfer properties as water, but it's not as corrosive. If oil leaks, you have a clean up issue and possibly a smell of hot oil, but if water leaks it can cause short circuits and bridge from power feeds to that nice stylish metal case.
    Remember, the PSU is directly below the LCS, yes there's a metal sheet between them, but it's not sealed watertight, so water can get around it. And it does.

    I don't doubt such a system could be made to work, but it's likely to me a far bigger job than swapping the old seals and hoses for newer/better ones.
    Silicone rubber hoses might be nice, but they have issues with gripping inlets/outlets. It's worth some research on the net for the well known and understood ways around them, but understand that stronger clamps can crush lighter weight spigots if over tightened.

    I've owned 6 or 7 European sports models and SUV's (and modified most of them in one way or another) with oil coolers (one had an oil cooler engine and another for the gearbox) some were a small radiator, looking like a smaller version of the water radiator (about the same kind of size as the LCS radiator), some were basically a pipe with wires on - to increase surface area. Aftermarket oil coolers can be found online, as can everything else you could need, it won't be cheap. You may find that a bit of creativity and some bits from the pick a part yard could give equivalent results for a fraction of the cost - take care with used parts they may be great or they may be trash, check them over carefully before handing over your cash, buyer beware.


    There's deposits alright, but you can also get corrosion too. Deposits can usually be cleaned off, but you may find contacts and circuit board tracks damaged or eaten away completely in some (usually small) areas. These can often be repaired, but it's time consuming and potentially expensive.
    I got a LCS from a dual processor G5 and examined it closely.
    If there's damage to the CPU boards, check the PSU carefully too.
     
  19. bunnspecial macrumors 603

    bunnspecial

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    #19
    When talking about oil coolers on cars, there's still the fact that they really only supplement the main cooling system rather than handling all the cooling.

    Some late air cooled Porsche 911 had(relatively speaking) HUGE oil capacities in a dry sump along with big oil coolers, but that's probably the extreme example and was at the limit of performance for what could be achieved without water cooling.

    BTW, the oil cooler in my MG is significantly larger than any computer LCS radiator I've seen :) . That car is also water cooled-the oil cooler was only widely used in North America mostly to protect against lowering the viscosity too much if someone used 10W-30 or lighter. For most conditions, the North American cars are considered to be overcooled-I actually put a blanking plate over the oil cooler in the winter, although I think it keeps the temperature gauge from creeping up too much when I'm crawling in traffic on a 90º+ day.
     
  20. oi! Suspended

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    #20
    What MG do you have? And what oil do you use?

    North American cars have a serious issue with cooling, a system designed to cope with the summer heat in Death Valley is massively over specced for winter in Alaska, and a system that's perfect for Alaska will over heat in Arizona pretty quickly.

    Blanking plate over the oil cooler sounds sensible, considering.

    All the oil coolers I've ever owned were on European models. They were all about the same size as the LCS radiator or smaller (the radiator type ones). I can only speak from my personal experience.
     
  21. Gav2k macrumors G3

    Gav2k

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    #21
    You can buy of cases made to hold oil check Linus tech tips for more on that.

    As for the oil idea. You could use a light gear oil but you'd need to check hoses and seals can work with it. That's the only concern really.

    From a performance standpoint you'll see no gain once the system settles. Yes the oils good at removing heat but it's not as good at shedding it.
     
  22. bunnspecial macrumors 603

    bunnspecial

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    #22
    It's a 1970 MGB and it calls for either 20W-50 or SAE 30.

    The fear was that North American mechanics/owners would just use the most readily available oils, which would probably be 10W-30. Bear in mind also that roughly 90% of production(~450,000 of 500,000) came to NA.

    I generally use 20W-50, especially for a complete oil change, and carry a quart in the boot :), but when you're out driving around in the sticks and need some oil at a gas station, sometimes 10W-40 is the best you can do. Heck, the NAPA I usually visit has been out of my preferred Penzoil Yellow Bottle 20W-50 since I bought the last of it a few weeks ago. I instead stocked up on Valvoline VR-1 20W-50.

    Unfortunately also, it's often desirable to use "not for street use" oils like VR-1 or even diesel oils to get the correct levels of zinc and other additives needed to keep old engines happy.
     
  23. MagicBoy macrumors 68040

    MagicBoy

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    #23
    I've seen them. Unless you've got a massive budget for something special from say Puget then your looking at adapting an aquarium.
     
  24. bunnspecial macrumors 603

    bunnspecial

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    #24
    I see a big problem with gear oils, or specifically with the common GL-5 spec gear oils(which are what you'll probably get unless you're specifically looking for GL-4). Water blocks are usually copper. The GL-5 spec allows for high levels of sulfur-based anti-wear additives(I hate handling gear oil for that reason, as it stinks) and those additives are known to attack "yellow" metals.

    I've seen synchro rings in manual transmissions destroyed by GL-5. The only MT I have now is filled with a GL-4 spec synthetic 90 weight formulated for MTs(in fact it's called MT-90). It's actually fantastic but a bit hard to swallow at ~$20/quart.
     
  25. oi! Suspended

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    #25
    Sweet! GT or roadster?
    A modern 20W-50, formulated for older engines is ideal. If you go for semi or fully synthetic, you could drop the viscosity a little for marginal performance and gas milage improvements, and extended service intervals.
    SAE30 is as light as that engine wants in sensible climates (ideal for Alaska and northern Canada) it was originally designed for SAE40. It's design is based on a 1920's side valve engine (as is the smaller A series), so some aspects are a little old fashioned.
    Shouldn't be anything inherently wrong with running a diesel oil, but they're not always keen on some of the modern additives.
    Plus, IIFC, these engines were designed and engineered to allow for a light build up of sludge!


    Or do you have the V8 version?
     

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