My 200B was like that.
I remember down the Mornington Peninsula one summer, I heard a funny noise from the engine. I stopped the car, popped the bonnet and realised it was the small amount of what that was left in the radiator boiling and bubbling.
Turned the engine back on, found a hose from the front yard of a house and topped it up and kept on going.
Brilliant! I had a 180B that was pretty much the same as yours. I delivered a lot of pizzas in that car, and it never gave out on me.