How-To Add Bar's Leaks to Cooling System

@bretb: Someone said not to add it to the reservoir (is that the same as the overflow tank?) Have you tried it this way before? BTW - Thanks for taking the time to answer!

To be honest, I don't use this stuff, I try to find the leak and fix it, but I understand why you would use it. I don't see why it matters where you put it in, it is supposed to travel through the system, so where you add it shouldn't make a difference.

Wow. This is one of those times when people should remember "my uninformed opinion does not constitute 'expert advice' for people needing true knowledge and answers." The way that sealant products work is that they swell and stiffen when re-exposed to air (as per a leak). So putting them into your reservoir (*against* instructions) gives you a great big blob of sealant and a gummed-up overflow hose and pressure valve. As far as how to handle the Yukon (or other cars lacking the obvious radiator cap/overflow set-up), you're going to have to sacrifice some coolant: open the large hose on the top side of your radiator, and pour it there, re-sealing, of course, when you're done. ( I think.)