Shuterdown, i used to use mobil 1 10-30 then i switched to 15-50 for the summer. i didnt have a guage when i ran the 10-30, but i did with the 15-50 and im at ~ 10 hot. i just bought castrol synthetic blend 20-50(mobil doesnt have 20-50) and ill see how that goes. i figure sythentic blend is just as good as full synthetic(and about half the price!) i know raising idle is no way to cure this, besides my car idles perfectly as it is......thaks fro all the input guys