I just had another radiator flushed & refilled with the 'long-life green' stuff which IS compatible with the other, older green glycol/silicate coolant. (IMO, using orange
or purple just begs confusion by anyone topping up a system.)
The crud in the linked pics reminds me of what happens when fatigued (but not 'silicate'?) coolants lose additive strength and aluminum reacts galvanically to grow it on itself or migrate elsewhere. (Hey remember when the guy who pumped your gas and checked your oil trickled your coolant onto a refractometer to check its PH?
How did that simple thing this ever get away from us??) Anyway, the non-green coolants are presumed to need less additive endurance to be aluminum-safe (galvanic corrosion) over their 'long life'.
It's hard to trust a flush to get all the old stuff out. It's also mind boggling that a pro shop's gear can vacuum a system with the engine running & not harm something somehow (overheat?). MSTB! (btw: Refill on my last one was 90%+ of 'rated' capacity & they let the chatty old guy watch close so I don't gobble all the 'complementary' donuts & drain the coffee pot.
) The OP is past all that now
( ), but I'd bet on a nice day a guy might wheel his rig out to a trailer and give a tractor a good go.
What if a service agent had switched coolants in practice (purple/orange) and not been aware of the potential issue when repeat customers showed up.
The stuff does NOT stay good as long as the color looks good. Changing it should be insurance vs a nightmare. (Accountability for the $$ over this?)