Downstairs bathroom sink doesnt drain

[Rozywyn]

I moved into this house about 2 months ago. After the first week I noticed the downstairs bathroom sink drained slowly. I snaked it and it worked well for a few weeks. It started draining slowly again and I snaked it again to no avail. It then quit draining completely. I then took the pipes apart only to find no clog. I snaked the main drain pipe from the wall but could only go in about 6 inches before it would go any farther. Didn't seem like a clog more like I couldn't get the snake to follow whatever bend. I went under the house to see if I could possibly pull the pipes from below and snake the other direction but they were these 4in monstrosities that I've never dealt with and I didn't want to break anything worse than it is already. Then Husband was using the upstairs bathroom sink and I noticed the water flowing up the drain downstairs. It now wont drain at all. Both tubs drain fine and both toilets flush fine. I've plunged the sink several dozen times over the last two days...still nothing. What can I do?

[Redwood]

I'd say that either the snake you are using is inadequate or, the technique is inadequate to clear the clog. The clog is not in the 4" pipe or, you would note many other problems.

Professional intervention maybe?

[HardonF]

helped me a lot this! thanks