Happy Holidays! I've been reading this forum a lot lately, especially on the problem about the thermostat. Here goes my situation:

*My 97 Blazer thermostat doesn't go past the 100 mark. I'm not sure if it's a gauge problem or the thermostat itself.
*There's lukewarm air blowing out of the vents when I turn on the heat.
*I did a coolant flush at an auto repair shop, which didn't help w/heating problems.
*I'm now trying to replace the thermostat myself, but I'm having a lot of trouble trying to get to it. First off, I'm not sure if I'm looking at the right thing. I followed the upper radiator hose to the engine block. I have a pic below:
http://tinypic.com/j65w15.jpg

*If that is the thing, how do I remove the bolt behind the radiator hose? I also put a pic of it below:
http://tinypic.com/j65yk6.jpg

Removing that bolt seems a little complicated, and looks like I'll have to remove some more parts that are obstructing it. From what I've been reading, it sounded pretty easy to replace the therm, so I don't know if I have the right thing. Any suggestions/ideas?

What I used was a 6in extension with a whobble or universal socket. If that doesn't work for you, the old standby, remove the egr valve and use a open end wrench. You also get to see the condition of your egr spring.

Alright, I was finally able to get the thermostat out yesterday, when I unbolted where the arrows are pointing at:
http://tinypic.com/j7ayqr.jpg

There was some leakage of the coolant, b/c I wasn't able to find the petcock on the radiator so that I could drain out some coolant beforehand. When I checked the level of the reservoir engine coolant tank, it wasn't at FULL, but it wasn't below the ADD level either. Should I put some more coolant in there? Is it okay to just add coolant instead of doing the whole flush procedure? Thanks!

Alright, I was finally able to get the thermostat out yesterday, when I unbolted where the arrows are pointing at:
http://tinypic.com/j7ayqr.jpg

There was some leakage of the coolant, b/c I wasn't able to find the petcock on the radiator so that I could drain out some coolant beforehand. When I checked the level of the reservoir engine coolant tank, it wasn't at FULL, but it wasn't below the ADD level either. Should I put some more coolant in there? Is it okay to just add coolant instead of doing the whole flush procedure? Thanks!
Yes, just add more coolant or water. and keep checking it periodically, because those engine are bad about leaky intake gaskets.