I wouldn't go for stop leak. You don't want to put anything in your radiator that could potentially gel up. Personally I've never used it, but I saw some videos on YouTube showing its results. Didn't look so good. If it's just a temporary fix, like your going to sell the car in a month or flush out cooling system in the near future, go for it. Otherwise if you are gonna try and use this as a permanent fix, I'd try and find something a little bit better.