I don't suppose any of you guys ever done this before... I have an aluminum radiator in the '32 that's had a slight leak in it forever. I don't want to change it out yet, so I always run a little stop leak in it to keep things going. Every once in a while I have to refresh it and it runs another 6000-7000 miles. I usually carry some with me just in case. Well, the other day i needed to go somewhere right away and I saw it was leaking again. I looked for my bottle of stop leak and I couldn't find it, so I walked over to the dollar store to get another bottle. I found what I wanted made the purchase and off I went. Got home, poured in 1/2 a bottle and thought everything was OK. I set the bottle on the bench and to my surprise... NO! Yes I did! I got snookered! I had to go, so I loaded up for the evening and off I went. I must have ran about 75 miles before returning home. In the morning I looked in the radiator and there was a slight oil slick on the coolant, but other than that everything looked OK. So, I went to town again, bought some radiator flush, more anti-freeze and another bottle of stop leak. It seems to be working OK, but I'm still not ready to change the radiator yet. But, I can see it's on the long to-do list. Moral of the story, look really close at the fine print before you pour it in!