Originally Posted by Travelin' Texans
The plug has small pin holes in it to prevent insects from crawling into the tube, but they are so small they gunk up easily, you should clean it up & either put it back or save til you find out if you need it.
Tex, yes, on closer inspection the plug does have a tiny hole in the center. I think I will leave it off and check it now and then since we do have a lot of critters that like to setup residence in RV's.
Thanks, that explains why it did not plug up until now. Still needs checking as that is a very small hole if you leave the plug on the tube.