Your thermostat is probably stuck open. A thermostat works as follows. When you start your engine the coolant is cool. At this point the thermostat is closed, not allowing coolant to run through the radiator--where it is cooled. However your water pump is always pumping coolant somewhere, and regardless of whether the t. Stat open or closed, the coolant is usually flowing through the heater core and the engine. As the engine creates more heat the coolant heats up also. When the coolant reaches 185 degrees or so, the thermostat opens and allows coolant to flow through the radiator. As air passes through the fins of the radiator, the coolant is cooled down to safer levels for the engine. If the thermostat sticks open or fails open, the coolant will constantly flow through the radiator and be constantly cooled. This will not allow the coolant to heat up thus you are left in the cold. Your engine will be happy, but unless you like to be cold, you will not be happy.
BTW-- a thermostat can stick or fail closed which will cause over heating and eventualy engine failure, so have your thermostat checked and/or replaced. Let me know how you make out.
Monday, December 24th, 2007 AT 11:08 PM