I would like to start changing the fluids in my wifes ATX more frequently istead of taking it in. Should I just drain and fill. What about the remaining fluid in the rad?

How does the shop do it? (assuming they do it right to start with)

Any recommended fluids or additives? Thanks in advice.

------------------------------------------------- 1996SE sports package, Duratec MTX No mods yet. 80K Kilometers. ------------------------------------------------- Wife has 1996GL Zetec ATX.