I picked up my survivor Buick back in late May and it did have some over heating problems. 3 miles into town and back would see it hit 200 and boil out(overflow). I did drain and add some radiator flush and rinsed that out. Still no cure. I then pulled the t-stat and bypass. The bypass was all gummed up with some sticky, greasy whatever, but seem to be in great shape. Cleaned everything and polished the brass shaft(which popped right out with a little tap). Reassembled everything and filled it up with distilled water. A couple of short trips to town and the temp gauge sat on 180 the whole trip.
On Saturday July 9 was the Reynolds Alberta Museum car show. A 25 minute drive at 55 mph and the temp held at 180. When we arrived, to my dismay there was a 1/4 mile lineup of antiques, customs, hot rods and others lined up to get in. After 35-40 minutes of idling up to the gate the temp had risen to 190 on the gauge( to my delight). I had added a catch can to the overflow and there about a cup or so of liquid in it.
Now to get some anti freeze in there and get the system back to normal.,,