I never had the issue with burping the system on my '93.

I tried it again tonight - still no luck.

The mech said that he pressure tested the radiator & it was fine.

The top hose gets hot but the lower hose doesn't so it definitely sounds like a blockage ... but what/where?

I'll keep playing wit it & let you know.

BTW, it's a fun car to drive & makes a great DD when you put 100 miles/day on it. I miss my '93 though - it was a stick.