Today I got the message the coolant level is low, checked when cold, it was below the minimum. I made the mistake of partially opening the coolant cap while engine temp was halfway to its operating temp. I heard a sound of pressurized air (sucked in or pumped out) so I closed it back.
Now I can hear sound of liquid moving (air bubble?) every 3-5 seconds, but only while the ventilation is turned on.
What should I do? Thank you.