In cold weather if not driven at highway speed for twenty miles to get the heat gauge up to the normal level for a extended period of time, it will cool of to the "C" mark on the gauge at city speeds and will not heat up in city driving. After it has set and cooled of the oil dip stick shows that the oil level is over filled. When it sets until the next morning, in below zero weather, at start up the engine will scream for about thirty seconds before it goes to cold idle.