Coolant issue FYI

Discussion in 'General Motoring' started by Rick Courtright, Jul 31, 2003.

  1. Hi,

    We've discussed the pros and cons of green vs orange coolant here
    before. Thought I'd relay something I saw on the news last night:

    I don't know how widespread the problem is, but apparently it's big
    enough to warrant a major SoCal TV station sending in their
    "investigative team" for what that's worth (news is slow?)

    Anyway, the report was on GM vehicles built since '95 or '96 using
    Dex-Cool coolant developing serious cooling system problems. The
    problems are rust and the coolant turning to some kind of sludge in the
    system, causing expensive repairs from overheating.

    GM defends the use of Dex-Cool, and claims every case they've
    investigated involved allowing the coolant level to drop to the point
    where the overflow tank was empty and there was air in the radiator.
    Owners and radiator shops dispute this, and there is at least one class
    action lawsuit in the works.

    Might be something to watch for if you're running orange coolant in your

    Rick Courtright, Jul 31, 2003
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  2. Rick Courtright

    Bill Putney Guest

    Interesting post, Rick.

    I know that late-model Chrysler cars are supposed to use the next
    marketing breakthrough (gimmick?) - which is the GL-5 grade of coolant.
    AFAIK, Zerex is the only maker of it. It is supposed to eliminate
    supposed problems of DexCool/Prestone Extended Life.

    I've seen some technical articles on the GL-5 posted on a Chrysler forum
    - I'll track them down and post unless someone beats me to it.

    Bill Putney
    (to reply by e-mail, replace the last letter of the alphabet in my
    address with "x")
    Bill Putney, Jul 31, 2003
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  3. Rick Courtright

    Bill Putney Guest

    I mis-typed - it's G-05, not GL-5 (I think I must've been thinking of a
    type of Subaru brake fluid or transmission grease or something).

    I got my education on it from thread on a Chrysler 300M forum
    The definitive post said: "Bill, you are right about DexCool being an
    OAT coolant. However, G-05 is an HOAT (hybrid organic additive tech)
    coolant, which unlike DexCool does have silicates in it. Chrysler found
    that the silicates prevent cavitation erosion of the aluminum water pump
    impeller. Indeed, water pump failure was the main reason they did not go
    with DexCool as an extended life coolant.

    The gross difference seems to be that the G-05 has low silicates (*not*
    silicate-free) - apparently it has been determiend that silicates
    provide some benefit in the coolant system (water pump).

    Does that mean it is the best to use in all cars? Who knows. The laws
    of physics are the same everywhere, but maybe there are subtle
    differences in materials or finishes. If I read the info. on the G-05
    correctly, it should be "best" for all cars.

    An informartive post from another Chrysler forum:"...e=UTF-8&selm=&rnum=1
    Here's an article referenced in that post:

    Bill Putney
    (to reply by e-mail, replace the last letter of the alphabet in my
    address with "x")
    Bill Putney, Jul 31, 2003
  4. Rick Courtright

    Emad Yousuf Guest

    yeah GL-5 is a gear oil rating.

    AFAIK the sludge problem caused by Dexcool was because dealerships
    were putting in stop leak pellets at time of PDI's. I suppose it had
    to be a normal GM practice to put theese pellets in their rad's before
    the vehicle left the dealership, but appearently since the switch to
    Dexcool this practice didn't stop, until GM finally put out TSB to
    dealers to stop adding pellets.
    Emad Yousuf, Aug 1, 2003
  5. Rick Courtright

    Hallraker Guest

    I have to wonder about the use of stop-leak pellets in a brand new car
    anyway. Maybe it is standard procedure with every manufacturer, but it
    doesn't seem useful to put stop leak into something that's new and therefore
    shouldn't be leaking.

    Hallraker, Aug 1, 2003
  6. Hi,

    I don't know how many manufacturers do (did?) this, but my mid-80's
    Toyota pickup came from the factory with some kind of sealer, and I
    understand Ford has also used it at some time. Why? Bill probably hit it
    having to do with certain manufacturing processes...

    Rick Courtright, Aug 1, 2003
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