hello , i am new to the forum and have a problem with my 1998 protege 1.5l se. my temperature hand on my car would drop whenever i turned on my heater. turned off heater and temp hand would rise only to blow out warm air. brought my car to the garage and the mechanic told me the radiator was bad. i took the car out and replaced the rad and thermostat only to end up with the same problem. the top hose on my rad gets hot but my bottom hose stays cool. any suggestions? water pump maybe ? thanks

 

the water pump will usually leak when it goes out, but i wouldn't rule it out completely. i would check the heater core.