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Recommended Antifreeze for 1985 400i

Discussion in '365 GT4 2+2/400/412' started by high123bid, Nov 18, 2018.

  1. high123bid

    high123bid Rookie

    Dec 20, 2013
    27
    Minneapolis, MN
    Full Name:
    Bo Andersen
    I have been advised to use simple Prestone. Opinions? Before you quote the manual, I have the manual but I do not intend to order Italian antifreeze the price of single cask. Aluminum must be aluminum. Regards, Bo
     
  2. raemin

    raemin Formula Junior

    Jan 16, 2007
    323
    Lyon (FR)
    Full Name:
    R. Emin
    Regular yellow antifreeze is fine. The lower the freezing temperature the less heat it can transfer. Glycol does not transfer heat as well as water, so pure/distilled water with zero anti-freeze plus wetting agent is better for cooling. I am not recommending this as antifreeze do have a few additional additives (anti-rust, joints lubrication, etc...), but the point is that you should not opt for a -50°C antifreeze when all you need is -25°C.
     
  3. raemin

    raemin Formula Junior

    Jan 16, 2007
    323
    Lyon (FR)
    Full Name:
    R. Emin
    More info here : https://www.engineeringtoolbox.com/ethylene-glycol-d_146.html

    50% water / 50% Glycol = 13.5% less heat transfer, liquid freezes at -36°C(-34.2F)
    40% water / 60% Glycol = 17% less heat transfer, liquid freezes at -52.8°C(-63F)
    60% water / 60% Glycol = 10% loss, -25°C
    (...)

    So the -25°C anti freeze dissipates approx 10% more heat than the -50°C anti freeze.
     
  4. Schumi

    Schumi Formula Junior
    Owner

    Jun 5, 2002
    691
    Missouri
    Full Name:
    Daren
    I am going to be changing my coolant very soon and would like to replace it with the best possible product/solution. Any suggestions as to products?
     
  5. raemin

    raemin Formula Junior

    Jan 16, 2007
    323
    Lyon (FR)
    Full Name:
    R. Emin
    There is not really such a thing as best antifreeze, there are antifreeze more or less suited to your usage. Stock dilution in the 400i manual is 15l of water + 5l of Glycol, so if you buy the regular -25°C antifreeze that's already more glycol than what the car had out of the factory.

    If you really want to do it by the book, in the 365 GT4 manual page 31 they do not recommend a specific AGIP bottle... There is instead a detailed explanation of the volume of glycol required in the antifreeze depending on your driving conditions, so you can go to your favourite store and ask for the liquid with the proper level of Glycol.

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    As a general rule it is a good idea to check the older owner manuals (and even stickers on the older models): tire pressure, oil and coolants are specified for various usage while on the most recent cars & manuals you only get a single general purpose figure.

    Nota : in the link I've previously posted the guy recommends a slightly higher concentration than the Ferrari manual in order to achieve the same freezing point, so keep some margin just in case.
     
    Schumi likes this.

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