There's always 2 ways to do things- the right way & managements way.

ya kevin, unfortunatly tech's are at the mercy of the management and what they decided needs to be stocked on the shelves. They usually tend to stock only the coolant that is compatible with the brand of truck they sell. The company i work for happens to stock 2 types, the green and the extended life coolant, anything else we have to get ourselves locally if we need it. It has to do with the inventory system and how we sell parts... if we dont move enough of one thing within a certain time period it gets taken away and as for things such as coolant and oils we are just at the mercy of what they want on the shelf. I think it has something to do with the aftermarket company we deal with, like unisource or promatch, TVH or premier parts, whoever the aftermarket is and what they push to the vendor/dealer. I'm sure there are other reasons i'm not aware of but this is just my take on how it works from my point of view.

And as for raytech's thing about GM's bulletin on mixing dexcool with green? They can say what they want about that but i've seen what happens when you do mix them and personally from my experience i just dont do it because of the extra work it creates having to clean out the mess it creates later on.

"should" use and what I get stocked on my service van from work is a wish and prayer you get what you get from the parts dept.

General Motors says in a TSB `conventional green can be safely added to dexcool, but now the system is no longer 5 year , 100.000 mile protection, it`s downgraded to 2 year.
You should use the type of coolant that the factory calls for.

I personally don't use the stuff, but have gotten accounts where the prior vendor did. It does seem to gum up the cooling system. The old fashioned green coolant containts silicate- it's the cleaning agent in the coolant- long life & universal coolant don't have this in it's makeup.

when you say 'universal coolant' can you be more specific on the brand and type? I myself have seen alot of this 'extended life' 50/50 mixed coolant (or the purple or pinkish looking stuff) being used in the place of the mfg's recommended type and its being fed to us that it is compatible.
But as you mentioned, i have seen tech's mixing it with these other coolant types and it does cause alot of corrosion, rust like buildup or 'mud' as i call it creating clogging in systems and so forth.
And of course if anyone has ever dealt with dexcool, NOTHING will mix with it period and it is highly corrosive if not changed out on the recommended schedule.