If you are getting heat and the engine is not running hot, chances are there is no air in the system. If you only added a half pint of coolant, that isn't odd unless you have to do it very often.
Do me a favor. Take a look through this link that may help locate a leak if one exists:
Also, I attached the procedure for refilling and bleeding the coolant. See pics below.
Let me know what you find.
See pics below.
Images (Click to enlarge)
Monday, October 24th, 2022 AT 9:18 PM