I was plowing some snow yesterday (finally got some) with my TO35 gas and something happened that's never happened to me before. As I backed up I saw a large puddle of coolant on the ground. Thinking about the aftermarket rad I put in this spring I thought maybe something let loose in it as it's not nearly as sturdy as the original one was. So I stopped the tractor and went to have a look and both the upper and lower rad hoses where sucked almost flat. My only conclusion was that the rad cap did not open up to let air in when it should have. So I very carefully loosened it off and had to pry up a bit on it to get it to come off because I was fighting the vacuum in the cooling system. Once I did so, the hoses became round again and everything seemed to operate normally. Aside from replacing the rad cap, is there anything else I should be concerned about engine wise?