OK this is a really strange one.

I had previously posted about a swimming pool pump where there were several leaks at various joints. I took the pump apart and reconfigured the piping and there remains one leak that is persistent and just won't go away. This leak is a slow leak on the outlet side of the pump where the 2" PVC male adapter threads into the female connection on top of the pump housing.



After I remade the connection, with RectorSeal T Plus 2 pipe thread sealant on the male threads, the leak remains (but slower).

I then took it apart and remade it again, this time adding some tape first, then the pipe sealant. Didn't make a difference.

I got some good advice on things to try, such as using silicone instead, or better quality pipe sealant, or using wider tape, or thicker tape, or wrapping it better, and spread the sealant more carefully, or using a clamp on the female connection in case it was stretched etc...

The first thing I tired was to wrap the male threads better without stretching the tape too much as I pulled, and spread the sealant more carefully. I then remade the joint, fully expecting the leak. As soon as I started the pump and it primed, no leak. So far so good. On the next day, the leak returned.

I was fully prepared to take it apart again, and follow the advice one by one until I solve the leak. However, some other more critical things demanded my attention, then a short vacation, and I came back yesterday to address this issue again, only to find the leak at the joint has stopped. Three weeks has gone by the leak disappeared!

I stopped the pump, restarted it, did it twice. No leak. The pump came on with the timer at 8am this morning, I checked the joint at 11am, no leak.

OK I am totally confused. What happened? Why did the leak stop by itself?



Edited 2 times.

Was there a significant difference in temperatures as in one day it was 60 and the other 90 degrees?

Vic, not really, it's been very warm like in the high 80s and 90s. The only difference I can think of is it rained A LOT two weeks ago for several days.

The pump pushed debris into the leak and sealed it (WAG). Like putting pepper in a leaky car radiator.

Paul, are you serious this may be the cause? Or were you joking?

If so is this now non leaking joint stable? Should I cross my fingers and hope it stays that way or should I continue with finding a remedy?

You saying if I didn't squeeze pipe sealant directly onto the threads, but instead sprinkled ground pepper and mix into the pipe sealant the joint would have been more "solid" LOL?

I'm serious sum. Long before they made the stuff in a bottle you can pour into a car radiator to stop a leak, us poor folks would pour a can of black pepper into the radiator. It would stop a radiator leak and that's 15 psi. It's possible that your pool pump pushed the remnants of a bug or a piece of dirt into the leak. I wouldn't expect it to be long lasting. I'd wrap the threads with Teflon then silicone sealant and let it sit over night. Use just enough tape so it can be taken apart if needed.