Good post Sewin
I'm also a fan of Prestone products, their antifreeze is actually good for 15 years although they do recommend you change it at year 10. It is also fully compatible with all colours including the red typically found in a Duratec, however when switching to the Prestone stuff a good flush is always recommended. Monty was well serviced before I bought him, but I always like to base line my car's maintenance schedule as you can never be 100% sure if elements like a coolant change were actually completed.
As I'm about to do a coolant flush/change it's helpful to know the capacity is 10 litres but you can only manage to drain down roughly 6 litres, of course this is common to all liquid cooled engines with a heater circuit so presurising the system with my hand pump cooling system tester has always been my solution as it forces far more of the coolant out.
Also, as I live in a very hard water area I'll be avoiding tap water completely, I've bought 25 litres of Triple QX de-Ionised water from Euro Car Parts, it's £16 which you could argue is expensive for water, especially as most of it will get thrown away during the flushing process.
https://www.eurocarparts.com/p/triple-qx-de-ionised-water-25l-553772350However, my thinking is I'm only doing the job very infrequently and whatever I ultimately leave in there after the flush and final fill will be sat there for 10 years, it seems a small price to pay particularly when I look at the state of the corners in my shower at home after just a few months of limescale buildup.
I also have a vacuum filler which removes the need for the bleed process, using my compressor the venturi design of the vacuum filler kit kit allows me to put the whole coolant system under significant negative pressure with all hoses literally sucked flat. The tank on the vacuum filler kit is filled with a fresh mix 50/50 mix of pure de-Ionised water and Prestone concentrated antifreeze, then with the system under negative pressure the tap is opened and the new fresh coolant is rapidly drawn in completely filling every void.
I've owned Monty for just over three years now, and despite his robust service history prior to my ownership I always feel it's better to do these jobs myself. It's the same with changing the brake and clutch fluid every two years, replacing the coolant myself every ten years is the only way to guarantee in my mind the job has been done and properly recorded, and of course the only way to ensure these jobs are done correctly with quality fluids.
