JasoninMN,, in all fairness I did go look at the bars leak site and the stuff you spoke of,,

 after reading the MSDS sheet does appear to be the same as I spoke of about the GM product.

What I an and a few others were advising strongly against is the commonly seen and known type of "bar's leak"  which is akin to road tar and will gum up the entire cooling system tighter than a bull's rear end at fly time.  When the engine's running around 170-200 degress it works fine,, then let it sit overnight,, it's no worse then pouring cement into the radiator.

This stuff   you can not even find here in any parts stores.  Only place it's ever been seen is the local GM dealership.