1998 e150 club wagon, 5.4 engine with 154k miles and front and rear air/heat. When the engine is warmed up the front will blow air hot enough to make you sweat but the rear vents blow ice cold all the time. Engine coolant is full and have not observed any leaks(not had to add coolant in the 25k miles I've owned it). Any ideas?

 

Once the engine is warm and you're sweating up front crawl underneath and feel the steel lines leading into the rear heater core----they should be pretty much equal in temperature.

Report back.

 

I will have to check that when I get home from work, which could be about 2 weeks. What are you thinking as far as potential problems? I've had cars bust a heater core before, but they poured coolant out as fast as I could pour it in.

 

The tall blonde (payback!) is wanting you to tell us if the lines are cold, hot, or what...

I'm betting they are cold and either the valve has stopped working or the lines are blocked.

Did this happen slowly over a winter season or two, or all of a sudden, like last week?

 

To be honest with you, I have no idea how long it has been like that. We have had it for about a year and a half now, but neither the wife or I had ridden in the back in winter until this year. The kids didn't complain last winter, but they hadn't complained this winter either. My wife rode back there a few weeks ago and immediately said it was blowing cold. Might have been messed up last year, might be recent.

 

Pretty sweet payback though huh?

 

I had same issue in an older van I had. The rear heater core was no good so the previous owner had shut the valve going to it. If I remember correctly, it should be on driver side (underneath about midway back) .
Hope it helps.
I'm having heat problems in my 93 Econoline now. Front heater core barely gets warm as does the radiator. Ran it in my driveway for 2 1/2 hrs and temp gauge never came to "C". (C - NORMAL - H on gauge in dash)
Put new thermostat in 2 weeks ago and zero change.
After running in driveway, both hoses and radiator just BARELY warm.
Any thoughts?