Black Tank Draining Sewer Smell

[treimche]

Originally Posted by Morich

I did a bit of looking and maybe a couple ideas?
There appears to be a wye that may make a fish tape go past the wye into the grey, instead of turning into the black? Maybe a clog between that wye and the black still?
Maybe the rubber grommet that connects the vent to the tank has broken down/slipped off but that would seem to allow smell all the time, not just as draining?
Click this or go direct here:
https://www.winnebago.com/Files/File...9/99wfl35u.pdf
Attachment 189437

The only openings in the black are the vent, the stool, and the big main drain. There is nothing much to leak like on the grey tank with sink, vanity and things like air admittance valves that can stick!

Thanks again for a great diagram. You're correct, when I stuck the tape measure down the vent pipe, it would have went straight down into the gray tank. So this still makes it possible that the pipe going into the black tank as a vent could be clogged or something. I need to figure out how to remove the wall panel from the hallway or bathroom so I can physically inspect this and see what is going on. I'm a little scared of what I might find though.

[Morich]

Yes, I'm almost always afraid before I look!
One of the things about RV is that they are so different than what we deal with in houses. That makes it both bad as they are built so lightweight but when it comes to taking them apart to look in the wall, it can be really helpful!
Compared to taking sheet rock off and repairing, the thin plywood can be lots more fun!

Lots of questions to look about but that plywood that is only stapled to the wall can sometimes be really easy to pry off.
If you can find the right place, it may be easier than expected to tease the trim off a corner and then gently pry the staples out of the small little wood behind it. Careful as it is easy to pry too hard so the staple pulls through the plywood!
I started out with Rv by buying old junkers and redoing them for our use and then selling. Traded sweat for equity?
Part of them were already so rotted inside that there was no question of what to do but it did give me some ideas when I finally got some that were not so bad inside!
And then once you do get to the pipe, it may not be that bad to cut and open to verify what's up.
If you get to that point and have not worked PVC before, be aware that there are lots of good things for repairing a cut pipe. It must be a common problem to have so many items made for putting them back together?
They come in different sizes to match what you have but basic idea is a coupling that doesn't have the ridge inside but totally smooth to slide on the pipe, place the pipe and slide back to glue over the cut!
https://www.homedepot.com/p/Charlott...00HD/203393296

Good luck on finding and fizxing! The tough part may be deciding WHAT!!