Top hose warm, bottom hose cold. Thermostat?
My truck has had very poor heat this winter. Seems to be a common complaint. It takes forever to warm up, and even at that it really never gets warm. Last year cardboard on the radiator worked. This year that is not the case. My lower radiator hose is cool while the upper is just warm after idling on a 40 degree day for about 15 minutes. It has some heat, but it cools off fast. Cold this be the thermostat? The fan is running, but it is not electric so it is always turning, right? I appreciate the help guys.