Has anyone tried Dot4 brake fluid in our car? I heard it was compatible, but is it worth it? Did you notice a difference?

you cant mix dot3 and 4 so you'll have to drain the system. refill with dot4 and remove air bubbles. I dont see why you'd need a higher grade of brake fluid. Most cars will never exceed dot3 boil temps unless racecar

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When I said compatible, I meant system compatible not mixable.
And I wanted to know cause I might want to get it on the track a little.

yeah it should be compatible dot 3&4 aren't to different in a way just boiling temps are different, if you want to do it the right way you will have to run denatured alcohol through your brake lines then run the dot 4 in after that it takes a long time and its very tedious the hard part is getting all of the bubbles out

DOT 5 is the stuff you don't wanna mix.
Car Talk - Brake Fluid

You wont notice a difference between dot 3 and 4 in our cars, in any situation.

i dont even see how it could in anyway make a difference unless your boiling your brake fluid which i doubt

You can mix DOT 3, DOT 4 & DOT 5.1, if you have DOT 3 in your system its fine to top it up with DOT4 or DOT 5.1 as they are all polyethylene Glycol based fluids, DOT 5 is silicon based and should not be mixed ever.