Hello good people.

2018 330i, roughly 42k miles.

Started my car one morning and got the low coolant warning.

Topped off the reservoirs with not much coolant. Before I topped it off, there was coolant inside, but it was just below the minimum marker.

Got on the road right after topping it off. Over 400 mile drive. No issues, no overheating, nothing. Perfectly fine.

Checked the levels the next morning, was lower than the level I filled it, but not where it was before.

No signs of any leak. Nothing under the car. Nothing on top or on the sides, under the hood. Nothing. Started the car, no issues or warnings. Let it idle for about 10 minutes, no leakage anywhere. No smells. No steam. Nothing.

Seen others say that this isn’t uncommon, but want to get it looked at. Should I simply get a pressure test? Also saw other say that the coolant cap could be an issue as well.

FYI: I don’t run the car crazy and always get the routine maintenance (oil change, alignment, tires, etc).