After I got off the highway last night from driving in 20 degree temps for about 15 minutes, I check under the hood and felt my radiator hoses, and the thermostat had not even opened! I checked the oil and felt it on the dipstick and it was cool to the touch. This is with Mobil1 10w-30, my first fill with synthetic in my Corolla. With dino, it would alsways run hotter, and the oil would be at least warm-hot if touched. Is Mobil 1 that good at removing heat or what? My Grand Am was the same way, even though it knocked bad with Mobil 1. I thought normal oil temperatures were something to be achieved in cold weather to burn off moisture and fuel. At the rate I'm going with Mobil 1 and cold temps, I'd have to drag race up a lonmg hill several times to get any heat in my engine it seems! Thermostat was just replaced also and it puts out great heat from the heater.