Ok thanks, for this grocery getter I will just pick up some DOT 3.Nope, both are polyethylene glycol based, just 4 has a higher boiling point when new.
And a higher boiling point when old, or “wet”.Nope, both are polyethylene glycol based, just 4 has a higher boiling point when new.
Yes but that's based on it being saturated to a certain point, DOT 4 and DOT 5.1 is apparently more hygroscopic than most DOT3 and is likely to absorb more water long term, in a system that's serviced frequently 4 or 5.1 is probably a better choice but in most road cars where the brake fluid is touched on very rare occasion, it's hard to say which is really better.And a higher boiling point when old, or “wet”.
+1Use Valvoline DOT 3/4 and you won't have to loose sleep over this conundrum.