largeo1 
I own a 2007 Pontiac Grand Prix that will not reach operating temp in cold weather when doing only highway driving. It will only reach operating temp if I do some city driving. The top radiator hose gets very hot, while the bottom radiator is only warm, but not hot. My concern is the engine my build up sludge in the oil or crankcase. I am getting plenty of heat in the car. When I say cold weather I am refering to 25 Degrees in Florida. Being a native of Michigan, this is not very cold weather.
I would appreciate some input,
Thanks
