If you look at your engine bay. to the right you will see a thick hose next to your airbox. follow it to the engine... the part it connects to is the Tstat housing. It has 2 bolts. take it off, and you will see the Tstat.

once the new one is in, be sure to bleed the air out of the system....

180 will keep te engine cooler, and most aftermarket pcm's are programed for a lower tstat.