This week I've done the new alternator (checked tension on belts too, as the PS one was loose).
Replaced expansion bottle cap and sensor. Cleaned it up and fix a security belt and a seat bolt, that had issues.
Took for a test drive with uphill included and it got hot, not too hot, but over 3/4 as before. At least the new cap did not let the fluid out, which helps.
I'll try this week to have the cooling system checked out by a professional, it's about time. I fear a radiator work at least... we'll see.
We are over 52200 miles now.