Having read a number of threads and now completed a few checks, I was hoping that someone maybe able to confirm wether or not my heater is performing below spec.   The heater is never hot even when the temperature control is turned to max and the fan on full (auto off). The engine runs at normal temerature - gauge always at half way and the heater input and output pipes are both very hot. I have run the engine hot with the radiator cap off for ten minutes or more to hopefully eliminate air lock