Am I missing a cap?

Jilong

This is a photo of the top of my 2018 Tab 400. The black pipe on the right is a chimney of some sort that leads into the bathroom. If someone could tell me where is leads exactly, that would be most appreciated. But my main question is, an I missing a cap or cover of some sort for that pipe?

ScottG

I'm not sure what purpose it serves on the 400, but it looks a lot like the air conditioner vent on older 320s. Those vents have a cap, and the lonely little prongs on the base of yours suggest it should have one as well.

bergger

That’s the vent pipe for your black tank. Looks like the cap blew off at some point. Might want to replace it. The covers are typically screwed on with the sales screws securing the other portion of the vent stack to the roof. Then covered with dicor sealant, all that gray stuff. Your cap probably cracked and broke  over time. 

BrianZ

We had a similar issue on our 320's A/C air vent when a tree branch pulled ours off, breaking a part, but leaving the screw on the base.  Fortunately, I had installed an outdoor temp sensor inside that cap, and the wire to the thermometer held it dangling outside, which I noticed in my rearview mirror.  I was able to repair it with JB Weld Plastic Bonder, and subsequently ordered a white one, in case this happens again..
Ventline 62334 White Plastic, Vent - V2049-01
https://a.co/d/h5R66wr
My repair has lasted 4 years so far.  At least yours only goes into a tank, so no worry about rain.  Mine goes into the A/C unit compartment, so rain would have been an issue until it was fixed, or at least covered.

JohninMissouri

  Yes, the cap is missing on your drains vent.