Makes me wonder if the aluminum on those cars was a different composition than the old Volvos. My 79 242 had the original brass radiator up until last year, I exchanged it for a new one but it turns out I didn't have to. I thought it might be clogged up, but the problem was the voltage regulator in the cluster making it look like it was overheating.
But ya, changing the coolant is one of the most overlooked maintenance issues, along with the trans and axle fluid.
Perhaps the new Volvo coolant recommendation? I use Peak Original Equipment Technology for European Vehicles in my modern Volvos, it specifically says "All Volvos". Somehow this is different than the other blue antifreeze they sell, Idk why it is different than Japanese or other cars. Probably isn't all that different.