AlumASeal Radiator Stop Leak is a small powdery type of product that you can pour directly into the radiator if you are having problems with a radiator. This isn't a permanent fix, and I probably would only use it on an older vehicle; however, my car now has over 300,000 miles on it. I know I got my money's worth, but I really don't want to have to buy another car at this point. My '93 Cavalier was losing antifreeze, and the local mechanic down the road said it seemed to him like it would be a major fix that would cost more than the car was worth. He suggested using Stop Leak. It is fairly easy to use. If the car is draining antifreeze, the overflow jug would be empty. I could hear a sloshing noise as I was driving around, and that clued me in to the fact that the fluid was low. The big issue with using this product is to avoid burning oneself - the radiator needs to be cool, so it's not a quick fix. It might take an hour for it to cool off and then turn the heater to the hot side. Then you have to open the radiator cap (which is a little bit challenging because you have to push down hard and turn at the same time, sort of like childproof medicine containers). Open the tube of Stop Leak and pour it into the radiator and add coolant to the proper level. Put the cap back on and drive the vehicle for a while to seal the leaks. **My Viewpoint:** I do think this product helps people to get a few more miles out of an older vehicle. It's certainly cheaper than buying a new car. It's made in the U.S.A., which to me is a plus. Unfortunately, the mechanic that told me the problem was probably too big to fix didn't notice that one of the hoses had a slow leak. It eventually blew out while I was driving down the road with my 3-year-old. Replacing a hose is one of the cheapest and easiest fixes on a car, and I wish I had taken it to someone else before trying this stuff. The problem kept getting worse and worse and I nearly sold my car when all it needed was a hose. I have known quite a few people who have used Stop Leak and it worked well - maybe for a couple of months and then it needed to be repeated. If you are having to use it more and more frequently, it would be best to find out more about the problem and decide whether it is worth it to fix it, in my opinion.