Has anyone experienced the heater in an XJ8 not working so well? Mine will make heat but its not real consistent as far as temp. There are not coolant leaks to be seen, it hasnt overheated in the 3 years I've owned it and it doesnt use any coolant as far a burning it.

 

Many many threads about heater performance, or its lack. You should do a search, and settle down for some reading.