Well after months of trying to figure out my strange heating issues and replacement of my entire cooling system I broke down and tossed in x2 smashed up GM tablets. Drove the car around for about 15-20 min to letit work and my temp stayed at a steady 180* again. Has anyone else used these? they seemed fairly cheep compared to aftermarket stop leaks but seemed the most safe from my research.

 

They are make by Bar's Stop leak. According to GM they put a couple in all the new cars on the production lines as a preventative measure against small leaks. They are safe to use in a reasonably well maintained cooling system. Most of the horror stories you hear about them plugging up rads and heater cores are from people with neglected systems that are already half plugged.

 

And, if you own a 4.1/4.5/4.9 Caddy, you better be using them.