кастроловский документ спецификация дот-4
http://www.castrol.com/liveassets/bp...onse_DOT_4.pdf
не нашел там упоминания о фулли синтетик, как и о том, что дот4 может быть минеральным.
вот тоже интересная статейка на аглицком
http://www.stoptech.com/tech_info/wp...fluid_1a.shtml
вот несколько выдержек "Does this make DOT 4 fluids better than DOT 3 fluids? Not always. Remember, the boiling points listed are minimums and there are DOT 3 fluids out there with higher boiling points than some DOT 4 fluids. The real differentiating factor should be that if you run a DOT 4 fluid you really should change the fluid more often than if you use a DOT 3, if for no other reason than the rapid fall off in boiling point with time."
"As a trailing note on the DOT ratings, if your car was designed for a particular type of fluid (especially prior to the development of DOT 4 fluids), you should make every attempt to stick with that fluid! For example, if your car was delivered with DOT 3 fluid, the internal components of the system (seals, brake hoses, and fittings for example) were specifically designed and tested for compatibility with DOT 3. Because DOT 4 fluids contain a different chemical composition, the system may not necessarily react in a positive fashion to the borate esters floating around in the mix."
а вот спецификация эльфа
http://www.elflubricants.ca/image/PD...0Frelub650.pdf
если сравнить эльф и кастрол, то ничем хваленый синтетический эльф особо и не превосходит кастрола.
понравилась фраза эльфа
"This synthetic fluid can be mixed with all other synthetic fluids whose chemistry is of the type DOT 3, DOT 4 or DOT 5.1," можно ее понимать и следующим образом, что синтетическими являются все жидкости класса дот-3..5.1