no heat coming out from inside the car?

are you saying there is no heat coming out of the vents as in the blower works but no heat comes out or the blower doesnt even work.

and what were you asking about the antifreeze?

I would first check the coolant level because if it is low the heater will be the first thing that stops working.

Here is a video to show you how:

https://youtu.be/GSE9skKnOgY?si=Y6pZXr771IDTM3ul

If the coolant level is okay I would swap out the temperature blend door actuator, but first go over this guide which may help as well.

https://www.2carpros.com/articles/car-heater-not-working

Here is the location of the temperature blend door actuator so you can fix the heater. it is #5 on the diagram. Check out the images (below). Let us know what you find.