Quoting Mark McDonald <tomswift@xxxxxxxxxxxxx>: . > > But this is what confuses me. If the thermostat isn't opening all the > way, wouldn't that make for a hotter engine, not a cooler one? > Mark, I am confused too. I just replaced my Lebaron's thermostat, because it appeared that it was not fully closing after the first warm up and shut down. So, if I drove the car right after I turned it off, it was running cold. In fact, I tested it the thermostat. I put it in a little pan with water, and when the water came close to a boil, it opened. When I gradually mixed cold water with the hot, I noticed it refused to close, even though another old 180 thermostat I had did close. So, I installed a 195 thermostat. You would think that the car would run a bit warmer now. Instead, it now takes longer to warm up. I had actually tested the 195 thermostat before installation. The car reaches operating temperature only if you hit the highway. My 68 Sedan is the same (180 thermostat, and a mechanical temperature gage). Even in warm days, it will refuse to exceed 160 unless you hit the highway. On a hot day at speed, it will climd to 200 or 210. It was even hotter before I had the radiator rodded out. Go figure... D^2, that is a mechanical engineer, and supposed to understand those "simple" things