My heater only gets warm, its still blows well. But just not hot. Could it only be my heater core? Or could it be something else? 89 mustang 5.0

 

I have the same problem with mine. I have replaced the thermostat, coolant sensor, and temp switch. Still only gets warm. I am getting ready to change the water pump and get a power flush and fill done. I was told that I might have a clog in the heater core which is not allowing the heat to get hot. I'll let you know if the flush and fill worked or not.

 

it could be the climate control ****... well the adjuster behind it.
when you turn the ****, it adjusts a flap behind there that directs the air over the heater core or over the a/c... mine came loose once and wouldn't blow hot air. i fixed it when i changed the heater core.

 

So, anyone else? Im thinking its not my thermostat, because temperature gauge is normal. The water pump is brand new, was replaced by the previous owner. So either a plugged heater hose, plugged core, a faulty temperature ****, or something else?