alfarocm

This us about a Nissan Altima 2003 2.5 S
Almost 95% of the time (on rare occasion it does not happen) I start the car (mainly winter) and I can drive to work (almost 40 miles) and the heater will not produce hot air, not even warm air. The fan will work, I will get full speeds, but the air will be cold, even after driving for 40 miles. I did find that if I stop after driving, say 10 miles and the car is warm, if I shut off the car, wait a couple of seconds (more like a minute) and then I start the car, then the heater operates normally. Full heat at all speeds. But if I do not stop to shut off the car and start it again, it will not get warm. The car has gone to Nissan and they can't find anything wrong with it. It has gone to 2 independent shops, and they say the same thing. One of the shops suggested changing the thermostat, but after checking the car (hooking it to the computer) they took that back. They checked the fluid of the coolant/antifreeze liquid and it’s ok.

Has anyone run into this problem? Anyone things they have a solution for this situation

Thank for taking the time to read.

Feel free to ask any questions.