heater problem

[l1j2h]

HAVE A 1999 Expedition EB 5.4. The heater blows warm air out front but not back. I put on new thermostat and the front heater core.
I check coolant flow in and out of the heater core. Both heater hoses are hot.
When I change from vent to front side or foot down side for heating, it is working very well.
I think that the blend door actuator is working very well. I think so.

What wrong with back?

Please help me.

Thanks

 

[l1j2h]

From Ranrex

Thank for giving a good answer.
Ranrex gave me a solution. I thought that I need to share for people.
I am thankful to him. I will do it as soon as I am possible.

His answer:
Yes, even though both hoses and the core were getting hot, I found out the rear heater core was clogged so water was not circulating through the system. It wasn't too hard to fix, I just had to pull out the heater core, hooked up the garden hose to it to clean the crud out of it, and reinstall. The return line to the engine was apparently also partially clogged, but after running the rear heater for a while the hose cleaned itself out and the heater works pretty good now. The whole job only took me about an hour and a half. It wasn't hard, Just had to remove several pieces of trim and quite a few screws from the blower housing. I know I need to flush the entire system but I haven't had enough down time yet, so it will have to wait.

Hope this helps.

 

[Bedrck47]

Just a question since you state that after you pilled the core and cleaned it with the garden host that the.
"The return line to the engine was apparently also partially clogged, but after running the rear heater for a while the hose cleaned itself."

What happened to the crud that was in the return line? Did you drain it out or just let it recirculate?

 

[IMINYOURCHAIR]

I recommend preforming a full cooling system flush, and do a through one at that. flush both heater cores separately alternating the direction of flow to wash it all out properly.

do note, if the core in the front gets too clogged it may be impossible to dislodge whatever it is that's there so be ready for a core replacement if that problem arises.

 

[l1j2h]

Thank You

First of all, I am thankful for your asking and giving a solution.
I have 1999 expedition 5.4 EB that doesn't have the rear heater core.

https://www.youtube.com/watch?v=CFTu6tmsGgk
After seeing it, I tried this.

I opened the the driver side of the back. I removed all trims, but I cannot see the rear heater core.


Right now, the front heater is very well. still the rear hearter is not o.k

1. Do you think that it is ok if I don't care?