I have a 1973 Custom10 Pickup and I noticed a puddle of radiator fluid yesterday morning. After driving it further I noticed it overheating and when I parked it was dripping coolant. I used as radiator stop leak formula and filled it with coolant and the leak seems to have stopped but it is still overheating. The coolant resivoir was boiling but no leak. The tube going into the radiator was not firm. Also, the temp gauge is a replacement(not stock) and fluctuates between 200-260. It will drop slowly and then slowly rise.