Friggen tick is annoying me
You are overthinking this. Get a length of hose, like 3/8 fuel hose, and stick one end near your ear. Be careful, if you have a BIG leak, you don't want an "earful." Just probe around with the hose, and if it's an exhaust leak, you'll find it.
If you think it's a valve, devise whatever you need, short length of rigid tube, etc, and attach to the end of the hose. Stick it down the oil filler port, and remove the PCV valve and probe down there. IF it gets louder, it's probably a valve.