Problem Water noise on board



As some of you probably know, I changed the thermostat in the car.

But a few days ago I noticed that when I turn on the ignition there is a noise on the dashboard as if someone blows with a hose/straw into a glass of water (those bubbles), I noticed that sometimes this sound also occurs when I accelerate the car.

Is this sound normal? If not, what could it be? What should I check?

When I topped up with antifreeze after changing the thermostat, was there air left in the system? Does this need to be vented? And if so, how?

Excuse me for asking so many questions, but that noise scared me a little and I don't know exactly what to do. I don't like to know that my car is "suffering".

I hope I can get some information, details from you.

Thank you in advance,