THERMOSTAT

192* or 195* is stock temperature. If you live in a cold climate (such as the Northeast), or if you like to switch out t-stats seasonally for late fall/winter/early spring, stick with this.

180* is the lowest temperature you'll want to go with in most cases. I usually run a 180* in my cars out here in the desert because it gives me a little extra margin of cooling in the 115*+ summers without making it TOO cold in the winter (because it only gets down to around the 60's most winter days). Again, if you live in any kind of a cold climate at all where temps get below 50 or 40* regularly, I wouldn't advise keeping one of these installed during the cold months - swap a 192 or 195* back in there until things get back up above 60 or 70* daily.

160* is overkill and almost the same as running without a T-stat, at all ... which sucks. Your car won't get up to proper operating temperature, your gas mileage will suffer, and your engine will suffer additional wear. If you're having cooling problems, then throwing one of these in there will NOT fix the issue - it's only a band-aid to cover a more serious problem in the system somewhere, one which is likely to only get worse with time. There are very few cases I can think of where running a 160* thermostat would make sense and/or be necessary.

Oh, and go with a failsafe t-stat whenever possible. If/when they crap out, they tend to stick open, which is far preferrable to having one that stays closed and overheats your motor in a jiffy.
 
I know people sat to stay away from a 160 and that they are bad and all, i dont run one, i run a 180. But we put a 160 in my buddies gt 40 h/c/i car and it runs great with it, knowing what i do now, i dont understand why it does. It has very hot air, hotter than the air in my car which has the 180 but thats becuase my heater core was bad. lol. But his car runs fine and doesnt throw codes. I dont know maybe his is just a freak.
 
I seem to be falling into the same situation as the last question.
Last month I installed a new water neck that had a tap for my mechanical water temp sender. I installed a new 195* fail-safe thermostat too. Since then, the water temp guage has shown a solid 185-190* during all drives. This is with the outside temps being anywhere from 60 up to 98*. Seems a bit cool to me. I had the exact same setup/guage in my 93 vert and I remember the temps were usually around the 200* mark.
I can't believe this beat up 92 hatch is running super efficient and keeping the temps that low on it's own. IS this what you mean by the stat might be stuck open? I know it went in correctly. I also checked it with water on the stove and it appeared to be working accurately.
What gives?
Ken