Plumbing leak

[Babin Farms]

Out of the blue I have a leak in the drain under the sink. The wife noticed it Friday that the basement floor was wet. I traced it to the main drain for the sink but when I dried everything off i could not get it to leak again until we run the dishwasher. The only thing I figure is the super hot water expands a joint where the glue didn’t hold well and opens up to leak. Everything under the sink is dry, where the dishwasher ties in is dry so I ran the dishwasher again and the leak seems to be coming from inside the wall, going down the pipe, hitting the Tee and then the floor. What gets me is it doesn’t leak with the sink water running.
Guess I get to cut the back of the cabinet out and replace the main drain line.

 

[Coult45]

NON-expert opinion...the expansion coefficient on that stuff has to be near zero...you're sure it's the waste line, and not something nearby that's trying to trick you into fixing the wrong thing?

 

[zipper]

Run a little cold water down the sink drain while the DW is running to test the expansion theory. What temp is your HW heater set at?

 

[TimW451]

Check to make sure the bottom of dishwasher isn’t leaking and the water is going across the floor to the hole for the drain pipe. That’s what happened to me. If you take the kick plate off of the dishwasher you should’ve able to check it.

 

[Babin Farms]

I’m 100% sure it’s the waste line. I’ll have to try running cold water with the dishwasher. I’ve never had an issue before even with pouring boiling hot water down the sink. Going to bring my bore camera home tomorrow and take a look.