alright, i am in the middle of flushing my radiator and replacing my thermostat because my truck was running cold. i drained the radiator and pulled out the old thermostat. the old thermostat was rated at 190, apparently it was just staying open or something. i put in a 180 rated one. i then filled the radiator and reservoir with radiator flush fluid and water and started the truck. i let it run for a while with the heater on full. after about ten minutes i watched the temperature guage rise to a little past midway and it seemed to stay there for a little while. rather than risk an overheat, i turned off the engine.

my question is, is the temperature rating on my new thermostat incorrect? or does having only water in the radiator mean that the temperature is going to get hotter? should i be concerned?

 

also, im not sure on the year of the 22re put in my truck as it was a replacement. but the truck is an 89 4x4, if that matters.

 

is it a real toyota t-stat
http://www.4crawler.com/4x4/CheapTri...tml#Thermostat

 

no, perhaps i should have looked that up beforehand. is the regular thermostat a big deal if it is just an initial overshoot, or can i run the regular single stage one?

 

The stock thermostat is 195* degrees.

 

Plain water in the system will cause the engine to run a bit hotter than usual.....yes. Even if you are getting temp gauge overshoot, it's nothing to freak about. I have had a single stage thermo in my 22re since I've owned it and it only overshoots in the winter when I turn the heater on before the truck warms. Even then, not all the time. It never gets past 3/4's (+/-) and eventually the thermo opens and the gauge goes back down. At some point, I will drill a dinky, little hole to stop that, but I'm not paying for a $30+ thermo. That would about fill the tank.