Yeah, I would hear boiling. I would also boil over and fill up the overflow tank, spilling a bunch of coolant out and compounding the problem. But once I had the system vacuumed, the air pocket was gone and the problem was solved.
I would not run the car for more than a few minutes at a time till you have that fixed. Taking a cab is easier than replacing a head gasket.
Yeah, electrical issues too. Most of these center around unholy under-hood temperatures from poor ventilation (especially the St165) which toast the wiring after a couple of decades.
I have had a lot of elec issues too. There is an open circuit somewhere that I have yet to find in three years. It will drain perfectly good batteries down after several days of sitting and eat through an alternator about once a year.
I have my engine out at the moment replacing all the gaskets, pumps and crap. While it is out I plan on replacing any questionable wiring and extending the harness around the firewall instead of between the head and intake mani in an effort to keep it cooler. Hopefully I will find the open circuit in the process.
You probably do not want to go to that extreme, but you could start by using a continuity light and begin pulling fuses till you find the culprit circuit. It sounds to me like you have an open or shorted circuit somewhere that is just enough of a problem to drain the battery, but not enough to blow a fuse.