When outside temperature gets around 35 there is only cool air blowing.
Temperature gauge is reading normal.
Flushed radiator twice. Nissan says there is an air bubble in the line??
I always have good luck by making sure the correct caps are installed on the radiator and degassing tank. Fill the tank up to the seam(slightly above full), make sure the radiator cap is in place(not the cap with the spring relief) and run it at about 2000 rpms for a few minutes. These things do a fairly good job of burping themselves. Switching the caps, or just installing spring relief caps in both locations, is an easy mistake I see often