I have a 98 Expedition that is putting out very little heat. I checked the hoses to the heater core and the inlet was hot, outlet was luke warm. Disconnected them and backflushed the core got good flow during the backflush. Changed the thermostate (195) at the same time. After reconnecting everything and filling the system with coolant I let the car run for 30 minutes before putting the cap on. It helped a little but still not very hot. The inlet hose was hot, oulet warm, not hot. Could I have air in the system? If so how do I bleed it? Could the heater core be bad? I have no leaks in the system. Also the temperature gauge will only get to nomeral operating temp while driving. At idle the gauge will start to drop. This is after I replaced the stat. What would cause it to overcool?

I would greatly appreciate any help. My wife is starting too get mad, and before I know it she will force me to take it to the repair shop, nooooo!

 

You might have a sticking blend door. It is located under the dash on the passenger side. Check to see if the door moves freely. Occassionally moisture from the A/C gets on the hinge and workings causing them to rust and/or bind. Not sure about the drop in temperature reading but to bleed any air out of the system, find a hose connection at the highest point reaqltive to the radiator and disconnect the hose there. Coolant should come out of this hose but if any air is trapped this will help to remove it. A good place is the hoses that connect to the throttle body to warm the intake air.

john

 

brentswebb,

Did you ever get this problem resolved?

If so, please post the fix. I have the exact same problem in my '97 Expy, & the wife has already demanded that I take it to the shop tomoorw.

HELP, PLEASE.

 

I would bet it's the blend door if the vehicle runs and drives OK. I am doing the repair this week and it is not for the faint hearted. I hope to post pics but you would need the $160 shop manual (helminc.com) and lots of time and patience. The best price I got was $800 to do the job but maybe I should have paid it.