Mishimoto Thermostat

ShutokuZ

You are correct sir! So, with the thermo open all the time, it is constantly circulating the coolant keeping the temps below the 150deg rating. A good way to test it (or even see if you suspect a faulty thermo), warm a pot of water to 150deg (or whatever deg rating on the thermo) and drop it in. You will see it open and how far it opens.

Edit, above is right, thermos usually fully open around 20deg past the rated temp. So, the 150 would fully open around 170, however it is still partially open at 150, causing coolant to still circulate, although not at full capacity. So, for DD around town, the car will stay around 160 unless on the freeway or pushing it hard on the streets. That is when it would get up to full opperating temps. I could actually see my temp needle moving in my Evo when I pushed it, then let off for a while.