New cooler mlt

It's cobbled together my first attempt at a Rubbermaid cooler MLT. Followed the directions from various threads on here and got most of my parts from home depot. I have it all together and have a very, very slow leak on the outside. Maybe a drop per minute. I kept the original o-ring/washer that came with the cooler on the inside. Cut a silicone washer to fit on the outside, have three fender washers outside and two inside and the whole fitting is pretty darn snug. I don't want to tighten it too much more because I could see it deforming the walls of the cooler. Any tips? Ideas to stop the leak? This is with cold water and it seems like leaks only get worse with hot water so gotta fix it and not just deal with a leak. Thanks in advance

 

99% of the time, the leak is due to liquid finding its way to the nipple's threads and no gasket is going to stop that. Also, you should never put a gasket on the outside because it will just keep you from seeing how much liquid is leaking into the insulation between the walls. In fact, I like drilling a 1/4" weep hole in the bottom of the cooler right under the bulkhead to more readily show leaks like this.

Please describe your assembly of parts on the inside of the cooler where the sealing really matters.

I highly recommend not gooping the whole thing up with silicone caulk.

 

I had the same problem, but was able to get the leak fixed. I didn't have the right size rubber o-ring on the outside and at the time I was not use any type of sealant. After replacing the o-ring and and adding some water pump sealant to the outside behind the fender washers, it worked like a champ. I did a 24hr leak check with both cold and 170F just to be sure. Good luck, Z