This is a double wide Mobile Home. Kitchen sink started backing up 4 days ago, no warning. I have double sinks, have tried plunging one, while wife held rags in the other. Put soda and hot vinegar down the drain, and used a 15' snake that went all the way down with no resistance. There is a clean out approximately 15' from the drain, so I tried snaking from the clean out back towards the drain. Went all the way in with no resistance? I am at my wits end, HELP!

You first removed the trap and snaked from there and then went up and snaked from the kitchen roof vent. Is that correct? Back to you, Tom

There is a clean out approximately 15' from the drain, so I tried snaking from the clean out back towards the drain

So you went 15 feet from the sink and then went 15 feet back toward the sink from the cleanout, right? If so, then you should have snaked out 15 feet PAST the cleanout away from the sink/cleanout...maybe find the blockage that way!

Here's what I would do:

I would remove the cleanout plug and then run water up at the sink until water filled the pipe and flowed out the cleanout. Then, snake the drain while keeping water trickling in the sink...when you hit the blockage the water will start to drain and you should hear it start to flow. At that point, snake back and forth numerous times to clear the area real well as you have located the blockage and want to do a good job clearing it!

If you do not hit the blockage after 15 feet then you either need a longer snake or you went through the blockage and may need a larger snake to clear the blockage.

Mark