Engine Cooling problem
1972 Other Mercedes Benz Models V8 Two Wheel Drive Automatic 92300 miles

I have a 1972 Mercedes 350SL with a radiator that has an Oil cooling radiator attached to the left. Where the oil supply (or return) tube attaches at the top there is a round nut (similar to a bathroom faucet supply tube).. the male end coming from the radiator is stripped and I can't get the nut tightened. so - of course oil is everywhere.

Can this be fixed or do I seriously need to buy a whole new radiator.