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dot 4?

bobski
ok you gear heads....whats the difference between dot 3 and dot 4 brake fluid and can i use 4 in 3 trucks?
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9 comments

Date Votes
  • babun
    Dot 4 has a higher boiling point while still almost the samething as 3.
    Dot 5 is completely different and should be used only where specified.

    https://blog.amsoil.com/dot-3-and-dot-4-brake-fluid-whats-the-difference/
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  • NeoBlackdog
    Dot 4 has a higher boiling point.
    I'd use what the manufacturer recommends for your particular vehicles.
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  • Smitty500mag
    bobski wrote:
    ....whats the difference between dot 3 and dot 4 brake fluid?

    One dot. :D
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  • Wulfmann
    Back when I tracked my 911SC I ran do5 but would boil it by lap 3 so installed Al Holbert racing brake coolers which solved the problem
    Also ran 110 octane which was not cheap but man did that boxer6 scream a beautiful song

    Back then if you ran dot 5 with racing brake coolers. turbo oil cooler and a 5 point harness you all but had a real race car and you could feel the true thoroughbred of a 911SC/Carrera and how felt so at home on a road course at red line

    Fun times
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  • select-fire
    NeoBlackdog wrote:
    Dot 4 has a higher boiling point.
    I'd use what the manufacturer recommends for your particular vehicles.


    +1
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  • babun
    select-fire wrote:
    NeoBlackdog wrote:
    Dot 4 has a higher boiling point.
    I'd use what the manufacturer recommends for your particular vehicles.


    +1

    For my 1970 454 SS Chevelle, the manufacturer recommends API SE rated oils. Have you seen any SE rated oils lately???? :shock:
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  • Smitty500mag
    babun wrote:
    Have you seen any SE rated oils lately???? :shock:

    Never heard of just SE before. The Society of Automobile Engineers (SAE) was formed in the early 1930s. Before that it was hard telling what you might purchase in the way of motor oil because there was no standardization.
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  • babun
    Smitty500mag wrote:
    babun wrote:
    Have you seen any SE rated oils lately???? :shock:

    Never heard of just SE before. The Society of Automobile Engineers (SAE) was formed in the early 1930s. Before that it was hard telling what you might purchase in the way of motor oil because there was no standardization.


    Point was what the manuf. recommends may be replaced by newer spec. products that cover the old standants.
    SE oil was the top of the line oil till about 1972, then SF.a few years later.....then SG.....Then SH... an d so on. till today,IIRC is SJ.

    All those later oils will be fine in the coreect wiegth for the 454SS.

    Backup_200005_read_oil_can_fig1.gif
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  • babun
    Barzillia wrote:
    bobski wrote:
    ok you gear heads....whats the difference between dot 3 and dot 4 brake fluid and can i use 4 in 3 trucks?

    Maybe.

    Because of its composition, DOT 4 may degrade rubber/plastic components in older trucks.

    If you are replacing because of boiling DOT 3 problems, you shouldn't mix the two, but might be able to drain and replace given the issue above.

    No maybees.
    Dot 4 will NOT degrade seals/rubbers in any car /truck spec'ed for Dot 3.
    They mix and play together well, but you will not gain any boiling point rise if you mix them.
    DOT 5 Is a different story...use only pure 5 no mixing with any thing else. And ONLY in vecicles designed for Dot 5 silicone fluids.
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