Chrysler Repair: 2003 Sebring Heater Problem, heater hoses, engine coolant

Question
This question is similar to the question you answered for Fran (10/31/2007).  The heater on my Sebring blows heat at ambient temperature if the engine is at idle or below 2500 RPM.  It operates find on the highway or when the RPMs are increased.  The engine temp gauge shows normal operation and has no indication of fluctuation or any engine coolant problems.  There has been no battery warning light or any other abnormal indications.  Did Fran ever resolve her problem and if so what was the solution?  What do you suggest?

Answer
Hi Michael,
I have not heard back from the previous questioner. I would suggest that you feel the difference in temperature of the incoming and outgoing heater hoses where they pass through the firewall in the engine compartment. If they feel similar in temperature and are hot, then that would show that the coolant is flowing well through the core. If one is significantly cooler than the other then that would indicate that the flow through the core is impaired. It may be a true obstruction or air trapped in the core that is causing the reduced flow rate. There is the vent hole in the thermostat of this engine so trapped air should not be a problem but I mention it. You might try reverse flushing the heater core with a garden hose connection to the return radiator hose and a disconnected supply hose to assure good flow through the heater core. I assume that this model doesn't have the more complicated automatic temp control heater where there is an electronic control of the mode (air mixing) door.
Roland