Ok, I changed my coolant.. I did the simple drain and refill.

about 1.25 gallons came out. I put in about the same amount.
i did take off the air relief plug..

the car doesn't overheat.. the heater works fine..

but the air relief never burps or overflowed..

what's going on? is that ok?

I used Nissan Fluid w/ distilled water.. new radiator cap also.

 

The system is not supposed to be burped; you can double check in the FSM but as far as I am aware, and I have done a lot of these coolant changes, burping is not recommended/necessary.