You can get a factory re-manuefacteured radiator for about $140-$165 in most places. I would do that. That sealer shit is only temporary and there is no exact time to how long it will hold. I had this problem about 10k miles ago and had it swapped immediatley. You have to remember that the radiator is under a lot of pressure and once the finger in the dam lets out it begins to go from there no matter what you. Also, if a cop sees a serious enough leak coming from your car, he can write you a ticket for improper disposal of hazardous material and then have your car towed. If he/she wanted to be a dick ofcourse...