I have a 1996 ford bronco with the 5.8 v8 with 211k on miles. I recently added a new water pump, thermostat, radiator hoses, alternator, battery, and ac compressor. My bronco has been wanting to overheat but never really climbs all that high and goes up and down constantly. Does not matter if i am in stopnand go traffic or driving on the freeway it still dord the same thing. I think it might be my heater core because i hear the fluid in the dash flowing as if there is still air inside. The heat also doesnt work and i already bled all the air i could from the system. If someone can help me that will be great.

 

get a real temp gauge on there so you know exactly what its doing. Get a motorcraft Tstat and make sure your fluid reservoir is full of fluid, this will help the system work the air out over time.

 

Do you still have the original radiator? and what coolant have you been using? tap water is known to create mineral deposits which clog the radiator in time.

 

sounds like its not full, did you fill the overflow bottle. how about the radiator cap.

 

have the radiator taken to a shp on have it boiled out at the least. If you want to do the best for your Bronco, buy a new radiator.
The cooling capacity does decrease due to aging and build up.

 

This was my first thought too. This will also test to see if the temp sensor is reading properly.