P-Trap leaks

[BobN]

I'm a homeowner, not a pro. My 10-year old kitchen sink p-trap is leaking. A quick look showed a split plastic nut under the drain. This is the nut that compresses the drain metal pipe to the 1 1/2" vertical plastic pipe of the p-trap. Local hardware store sold me a new nut. I installed it and it seemed fine. I used silicone grease on the plastic threads, thinking that would make it easier to tighten and loosen in the future. To be safe, I only hand-tightened it. I didn't want to split the new nut.

Two days later, I noticed leaking from the other side of the p-trap. You can see the leak in this photo.

I used a long wrench to tighten that large nut another turn and the leak seemed to stop.

QUESTION: Does that large nut really need to be very tight? How do you know when it's enough vs too tight?

Thank you.

 

[Reach4]

I would take the opportunity to bring your installation up to code and fix this problem at the same time. I would install an AAV and use a slip joint 1.5 inch P-trap. NH allows AAVs. There are many posts on implementing this. If you have trouble finding one, say so.

As to why you are leaking, I wonder if there is stress. A slip joint trap can relieve stress.

For now, what if you loosen the new nut, loosen and retighten the leaking nut, and then re-tighten the new nut, does that make the current leak go away?