I've had some heating problems with my '04 XJR. Not uncommon, but I'm out of ideas. There was no heat, so I replaced the auxiliary water pump. After that there was some heat on the passenger side. So I replaced the heater core. Now there is some heat on both sides, but it's not exactly hot. I have the temperature set at 88F and the air coming out of the vents is low 60s. What else is there to do? Are there valves that fail? Is there something else that causes problems? The system is fully bled, so I don't think there is an air pocket somewhere.

Thanks!

 

Possible failure of water pump vanes or possible partial blockage of thermostat housing (plastic). I suggest that you should replace the thermostat first.