2 bucks,
I am certainly not referring to all Cat dealers nor am I trying to criticize them in any way. For the most part they are a good outfit. I was thinking of having them do the ELC conversion and I asked how they would do it. I was told by the service manger that they would drain, use a "cleaner" additive to flush, drain again, and fill with 50/50 ELC. Maybe this being a very southern dealer they do not worry about exactly getting to 50/50 dillution rate and this falls in the catagory of good enough. This is probably not an issue in front engine trucks or heavy equipment which is most of their work. They probably drain very well.
The parts department definately did not stock ELC concentrate, I had to order that for my own use which came in on the parts truck in a couple of days.
I think if you already have ELC and do a standard drain and several older gallons are retained that is probably just fine. You are repleneshing the chemical components to new in 90% of the solution and the rest gets dilluted into the mix. This coolant is very stable and has a very long use life that most of us will never have to worry about. Like with any auto transmission oil change, you are working with dillution and a partial fluid repelenishment as a routine.
I think the bottom line is it is probably wise to know how the work will be done to your coach for things that are not so routine, and it should pass your own "muster test" before you give them the green light. The Meritor disk brake lube procedure is another procedure that I would want to know how the work would be done and what grease will be used. Just my line of thinking....hate surprises.
Later Ed