It is running to warm, and I have been told so many different things are the problem, but no one wants to put their mouth with truth and fix it. I think that these people are just talking to make it sound good, because they don't really know what the problem is. So, I need someone that can tell the truth and not lie.

Your right. The problem with the 97-2004 Yukons is the radiators and the collant systems, and no one really knows what is wrong with them. I have had my 99 Yukon for 7 years and I love her. I spent a ton of money to find out that the only thing I can really do, is make sure the coolant is kept topped up. Coolant is cheap and I only have to top it up every few months, but it seems to have solved the the over heating issue for me. You can replace the rad if you want but it only seems to change things for a few months at best. I went through 4 before I gave up.