New to busses

[Tedsoldbus]

It is a bus. You are going to worry. It is what we do when not sure. Happens even when we are sure. I was born that way. I think that is why they made me the assistant maintenance officer in my squadron. Lots of worrying in aircraft maintenance. Can't pull over to a nearby cloud and see what is hissing...
I still worry. I use lots of soapy spray bottle on things I don't think are leaking. If nothing bubbles, it just makes it cleaner. Might try the soapy spray on anything you think might be leaking. It will tell you fast. I found a propane leak behind my refrigerator shut off valve with two squirts of soap. Two "repair" shops could not find the source of propane smell for the previous owner. Bet they didn't try soap.
Best of luck. And remember with these old buses. It is always something. It's never nothing.