First off sorry about the last post in the wrong place.
I tried flushing my heater core and this didnt help, I have flushed it a number of times over the last couple of years and it didnt help. I also think that at some point someone has filled the radiator with river water or something as the coolant that comes out when you flush is muddy red in color. I have got this pretty much cleared up but still dont have a heater. when it is blowing out the dash or the floorboard it gets pretty warm but if you put it on defrost it is almost as cold as the A/C. Any other suggestions??????:d unno:

 

the defrost is basically AC with heat behind it - do maybe you have an issue with a vacuum line not opening and closing the right pathes - if you get hot air when its on heat then your core seems fine

 

Is the blender door moving when you change from heat to defrost? Is the heater valve opening all the way when you move the lever to the red side from the blue side. When you flushed the heater core was the return flow as good as the input flow or was there the feel of an obstruction or partial obstruction?

 

all valves seem to be working fine but as far as the heater core goes it did not seem to be coming out at the same rate it was going in at, and it was the same regardless of the flush direction

 

You may need a new core but they are not an easy replcement as I have mentioned. Dash disassembly is required.

 

never replaced one on an xj but they are a PIA to replace on just about every automobile ever made i think.

 

Its about a 4 hour job with air tools, its a fairly big job but not difficult

 

do you know if you have to pull the A/C components to get to it. I have had a problem with that on other cars/trucks