Ok, well i recently flushed my cooling system, had a new thermostat put in and a new cap as well and the heater would burn your fingers if you got them too close to the vent. Two days after the cooling system service the heater went back to its previous state; luke warm and never hot. What could be the problem? I checked the fluid and it is full while hot.

 

Good question. I have the same problem, but I have not fixed (or tried) because I live in FL. I would be curious as to the fix though. Let me know if you figure it out.

 

Well I ran car at high idle till coolant in in engine went down a bit then filled up to top of overflow . I did this acouple o times and now ihave hot air again. Seems it can get an air pocket in the system and I just needed to keep addind coolant till it was gone