My 2001 xj is not blowing hot air when I turn the heater on. I have a fairly new heater core. I have a 195 degree thermostat and a almost new water pump. The blower motor is working. The damper doors appear to work when I change positions it blows at the indicated place....floor, windshield, front vents, etc. however, when I turn the temperature control **** it doesn't seem to change from cold to hot. I have also back flushed the heater core to make sure it wasn't clogged. Any suggestions? It's getting cold out side!

Rick

 

heater core hoses both hot?

 

Yes both are hot. I back flushed the core from the hose ends. No obstructions.

 

im convinced the water bypasses the bulk of the core, somehow, in/out, with so many just like this. i have heat in my 2000, did all the stuff with my 1998 with little heat?
any pix of the naked core?

im thinking a good part of core stays plugged up,water goes thru a small part.

 

I had a new ac evap core put in this past July and had a heater core put in at the same time while the dash was out. So the heater core is only 5 months old. I back flushed it this morning with a hose. Seemed to flush good with nothing coming out but clear water. I didn't expect anything being as new as it is but running out of things to eliminate. I don't have any pics. The temperature control dial seems to have no affect on the temperature. There's not much to it and not sure how to check it other than to replace it. Or I'm thinking it could be a damper door (or whatever it's called) is not opening allowing the fan to pull air through the heater core.