2003 Ford Explorer heating issue.

[Mbgalanos]

Lately I have noticed the heating on my Explorer has not been working right. I am getting cold air blowing thru the vents even when the heat is turned up all the way and the engine is warmed up. I replaced the thermostat to see if that may be the issue. The heat works fine as long as the vehicle is moving forward. When I come to a stop the heat starts turning cool again and then resumes when I move forward. I have not experienced this before. Anyone ever experience this problem before?

 

[Devlin]

I have the same issue also in a 2003. My temp gauge doesn't show any change from before and indicates a normal temp so I'm inclined to think it's not the t-stat.

From what I've read so far it's either a stuck blend door or a clogged heater core but I'm not sure how to determine which one. I'd like to know before I just start pulling parts becuase neither is easy to deal with.

 

[BrooklynBay]

Welcome to this forum! It sounds like you are either low on coolant or there is a vacuum leak.

 

[Devlin]

My coolant level is fine and I don't think I have a vacuum leak because when I select the heater to Max A/C the recycle door opens properly.

 

[Mbgalanos]

I replaced the T-stat and noticed no change. Heat works ok when the engine is in drive and running forward. No heat at all if the car is in park. Any other suggestions on how to determine if this is the heating coil or blender box?

 

[Devlin]

How many miles do you have on your explorer? I have 130,000 miles so I'm inclined to think that my problem is a clogged heater core. Eventually they tend to get clogged so if you're higher miles my inclination would be to suspect the core.

I'm going to disconnect both hoses and try flushing out the heater core but I need to wait until I get some warmer weather.

 

[Mbgalanos]

Thanks Brooklynbay. I checked the coolant level and noticed that it was low. After adding about a gallon of the 50/50 premix at Advanced Auto Parts, I cycled the engine and climate control knob and started getting heat again while in idle and park. Appreciate all of the comments and suggestions. This beats the hell out of having the dealership rape me for a grand and tell something different was the problem.

 

[BrooklynBay]

Thanks for the update!