I did some work on a 1990’s Toyota Corolla recently, and I had to take off the hose coming from the heater and back to the engine. About 1 cup of coolant leaked out. I just re-installed the hose after the repair, and didn’t bother to bleed the cooling system. My plan was to just top the cooling system off after a week or two when everything equalized.
Actually, I’ve never bleedthe cooling system in any car I’ve worked on, but usually working on cooling systems involves draining the whole system, then refilling it by filling the radiator and leaving the cap off and topping it off until the thermostat opens, which I think bleeds the system. This time I didn’t do anything except just to replace the hose. Then I wondered if that could have created and air pocket with some undesireable effects. What should look out for?