The Haynes manual shows that the thermostat for my 83 GL wagon should open up at 190 degrees, but the Japanese auto parts store sold me a 180 degree thermostat, saying it was "OEM" and would work just fine. I haven't installed it yet, because that doesn't sound correct to me. Is the 180 o.k. to use, or should I try to find a 190 somewhere (where?), and stick to the manual? What would be the benefits/consequences of using a 180? Thanks for the help.

180 should be fine. I've seen them as 185 also.

 

Personally, I'd just go the dealer and get an OEM T-Stat. Numerous people here have had problems with aftermarket T-Stats. If there's a dealer near by, most they'll charge is you is like $15, and you know you got the right one.

Most oem thermostats are 195. The higher temp allows for better fuel atomization, and it allows the oil to reach optimum temp as well so any moisture can "boil off". The 180 thermostat may give you more power due to the cooler intake charge and cylinder temps, but it's barely noticeable, if at all in the little engines we have. Just remember, the thermostat temp is the coolest the engine will be after warm up, it does not mean it will stay at that temp. After it opens the temp can and will increase under load. It's best to get the correct temp, the carb, timing, emmisions, etc are designed for it.