Strange Kitchen Sink Problem

[bren99]

I have a double kitchen sink in my fifth wheel. If I run water in the sink it will not drain. I have let it sit a couple days and I look and the water is gone. If I run water again, it will not drain out. I have tried everything for sink clogs, used a snake and nothing happens or changes.

Has anyone run across this before? The sink is either clogged or it isn't, so why does it suddenly drain all the water out?

I need my sink back! Any ideas?

As a side note, my bathroom sink and shower drain fine.

[mtofell1]

Okay, maybe a dumb question but I've seen this topic go around RV message boards too many times with people smacking their heads once they learn - you don't have a separate galley gray tank do you?

[momentum_rv]

AAV (air admittance valve) under the sink if not working sink won't drain properly

[fla-gypsy]

When was the last time the gray water tank was emptied?

[Halmfamily]

If it's in an island there is an air vent under the sink. Remove that and see if it works. If it does go to Home Depot and purchase a new one. Good luck.

[Mike_Taverniti]

Find your mechanical plumbing vent, usually at kitchen sink or bathroom sink. $ 6 at Lowes.
Problem solved

[bren99]

I was thinking it might have something to do with something like that- air lock but had no idea what to look for. I will try the roof vent thing. Will let you know.

2oldman- No, I didn't sit and watch it continuously. Suddenly may be a poor choice of words, but I would look at it one minute, the sink is a quarter full of water and a half an hour later I would look and the sink would be empty. And yes, I did take apart the drainpipe. Thank you for your input.

[2oldman]

Does trying everything include disassembling the drain pipe?

bren99 wrote:
I have let it sit a couple days and I look and the water is gone....The sink is either clogged or it isn't, so why does it suddenly drain all the water out?

How would you know it suddenly drains out unless you sit there and watch it? I must be missing something.

[TakingThe5th]

lovetotow wrote:
Maybe your sink roof vent is clogged causing an air lock

X2.Try running some water down the roof vent to clear any clog.

[lovetotow]

Maybe your sink roof vent is clogged causing an air lock