Just switched to Amsoil

[Tonavi]

For the first 5 oil changes (up to about 21,000), I was going to the dealer (who uses Mobil 1), and the car ran great and I got my best mileage ever using that. At sometime around 21,000, I put in Valvoline SynPower, since I work at Valvoline, and I noticed my heat temperature at the vent was going to 170, whereas before never went over 160. Also, the coolant hose is rock hard and I never noticed that before, leading me to believe that the motor is running warmer than it used to. I came across Amsoil at a great price ($7/qt) and put that in with a WIX filter. I want to use synthetic to keep the inside of the motor cleaner and preventing leaks down the road when the miles get high.

The heat is still around 170, but is that since it's summertime now and it heats up faster, or is it running too warm? I ordered a ScanGauge today to see how warm it actually is getting. I also want to get 45+ MPG for a whole summer instead of 40 that I have been getting so far on synthetic (43 on dino).

Any thoughts or ideas? Thanks in advance.