What would cause a 1998 Buick Century to heat up even after the thermostat was changed?

Answer 1

I am guessing you mean overheat. To "heat up" is normal. We want the car to heat up, but to go any higher than about 225 degrees would be to overheat, and that would be bad. If that is what you mean, then there are a number of things that could be causing it. It could be as simple as to high of a concentration of anti-freeze to water mixture(should be a bout 50%), to something as costlty as a blown head gasket. The water pump could have the impellers rusted off and not pumping, the radiator could be stopped up, there could be air trapped i the cooling system, there could be an obstruction to air flow in front of the radiator like leaves trapped in front of it, the cooling fan may not be working, even the thermostat you installed could be defective or installed backwards. It boils down to this: You either have a coolant flow or an air flow problem. (I am including the blown headgasket in the coolant flow catagory) As simple way to narrow it down is when then car is running hot, put your hand on the radiator. If the radiator is hot, then you probably have an air flow problem, see if the fan is working, or there are leaves in front of the radiator. If the radiator is cold, then you have a coolant flow problem, something is keeping coolant from flowwing into the radiator. (water pump, ai in the system, stopped up radiator, etc)