My 1984 Westy (original 1.9L) will consistently "burp" coolant from the
overflow tank if I fill it anywhere between the Min and Max marks. Highway
driving is fine, but if I do a little stop-and-go driving, the temp gauge
will creep above the halfway point and at the next stop I can be virtually
guaranteed of some burping coolant from the expansion tank. What gives?

Thanks in advance,

Kris S. Seago