Stink from Air Admittance Vent
I had one of these vents attached to the sink drain in my kitchen island. A month ago, we started detecting a smell - tought it was the garbage. AFter several attemps to stop the stink I noticed the air vent up behind the sink. I put some plastic wrap on it, held in place with a rubber band, and stink went away. Saw no impact on drainage - so I took the vent out and put a threaded plug in. Fixed!
This week detected a smell coming from a butler pantry sink. Looked underneath and saw another one of these vents. Used the same approach as above and stink went away. But this time, I can see that the water drains slower. Haven't installed the permanent plug on this vent yet.
Do i need these vents? Aren't they supposed to bring a little air in to help drainage but not let smelly gas out? Why the smell all of a sudden - is that normal? Seems odd to me that both vents started emitting the smell within a month of each other.