Washing machine drain backing up
My washing machine drain is backing up. The machine is about 4 or 5 years old and I live in a 57 year old house. Never had a problem until now. I've already had a plummer out that snaked the pipe (1 1/2 inches) 100 feet and he snaked the vent on the roof 100 feet but its still backing up. He even checked the trap for the house but that's clear. Nothing else in the house is backing up.
Now here is my question. Outside the house about where the washing machine is is a tiny pipe sticking out. It comes out of the house and it bent 90 degrees toward the ground. The original owner also used to like to do things on his own. A lot. Could this be the vent for this pipe? I can't see any of the plumping and I can't get to the crawl space. The plumber does not no what's wrong so he just wants to cut into the wall put in a L joint and run a new line to the sewer. That's a lot of money $1500 to be exact plus the cost to repair the wall and maybe even the stucco outside the house and cutting into the drive way. I just can't help but wonder if that little tiny pipe could be air vent and if blocked causing the back up.
Also just a note that when the water backs up and I stop the washer to let the water go down it is sucking air when it gets down to the drain.