I have a 1974 318 FWC engine with a coolant reservoir that overflows everytime I run the engine. I have put an empty juice on the overflow hose to catch the coolant and reuse it, but a day long usage will run the reservoir dry. The coolant is clean and not discolored by oil, exhaust, or rust. I have tried a few new caps with no success. I don't know that it matters, but this engine also has the hoses sending coolant to the cabin air heat exchanger.