Synthetic oil heats up a lot faster than dino. I'm sitting in traffic today and watched my oil temp gauge go from 180F to 290F in less than 10 minutes. The water temp barely moved during this time in traffic. I do have a factory oil cooler and the AC was running. I use to run 10W30 Pennzoil and now it is filled with Mobil One. When I ran dino I never remember the oil temp ever jumping up this fast. I sat on I-95 in Miami two years ago in 96 degree heat and the oil temp rose but only to about 220 degrees.