Hello, I'm new to the forum but I could use some help.

I have a 1991 Nissan D21 Extended Cab 2.4L 4 cyl that was my dad's from when it was new but has been mine for 9 years. I will personally testify to this thing's 'stubbornness' but right now, my temp gauge has been getting to that near warning line. Both me and my dad are pretty sure it's the thermostat since we just put in fresh water and coolant, but here's the thing: We're not sure where the thermostat is, or how exactly to get to it. If anyone could provide advice or point out on this pic where it is (I know it's not very good: I'm a biochem student who has a knack for computers, not engines) I would be sooooooooooooo grateful.

Umm....I have an 89 truck and the engine is different.... but on mine the upper hose coming out of the radiator hooks up to it!! Its secured by two bolts!! I wish I had the same engine so I can help u out!!

Heres a link to a video that shows a quick shot of where the thermostat is.... its where the hose ends!!!
http://www.youtube.com/watch?v=CqNPkt7esJ0&sns=sms

*This has been edited, since it was written when I was mad about something away from the forum. The original comment has been removed and rewritten.*

Dang, with all that stuff there, is there even a way to get to it without taking out the rest of the cooling system?

Like I said before, I'm not sure about your truck but on mine, No!!! On the video he was doing the water pump so he had to remove a lot of stuff but for a thermostat I'm pretty sure u don't have to remove any thing except for those three bolts securing the stat!!