Small leak in black water tank

[InspectorDread]

My unit is a 1987 34' Excella. On my last trip out (Mobile to Houston), after a few weeks, I noticed a very small leak ( one drip every 20 seconds) coming from the covering of the black tank.
I am very reluctant to take this problem to an RV repair center. Most likely they will try and sell me a very expensive and unnecessary new tank.
My question is this. Can I fill the tank with clean water and add some kind of additive that will seal a small crack?

[overlander63]

I had limited success with BarsLeak in a black tank I was working with, I put a couple of bottles of the stuff in the black tank, and put about 8-10 gallons of fresh water in the tank, then drove around for a while to get things sloshing around. It stopped the leak for a few months, but eventually I had to make a real repair.
I have something called "Slap-A-Patch" te a patchncover the hole in your tank to us uve tod haut you woulhat supposedly works on all tanks and RV roofs, b

[lsinclair]

I'm not familiar with tank leaks. However, with respect to the last post, stop leaks products like "BarrsLeak" are most effective when fluid temperature is 100+ degrees or better and the fluid is able to circulate.
Good luck, Larry

[Smokin Camel]

I ran into a minor crack in my waste tank (black & grey) . A local RV dealer that I often get parts from said he would not weld them. They tried it years ago and there was a high failure rate on those repairs.

My research on this forum and from a couple of RV dealers led me to buy a new tank. The two best avenues are either a fiber glass tank or an order for one to Inca plastics. There is a good forum and some threads on making a tank, using your old one for a mold. Inland RV sells fiberglass tanks that seem pretty tough from what I read. I ended up getting one from Inca as they still had the mold for mine, that wa also before I read about the glass tanks from Inland.

It was a pain in the @$$ getting that thing out and I am not looking forward to "adjusting the plumbing when I put the new one in. On the other hand it was 35 years old as was the dump valve. I ended up with a different model dump valve that i will modify to fit.

Getting back to the main point....high failure rate means there is a real possibility of removing the tank a second time. I guess you have to decide if it is worth it. The Inca tank was a couple hundred bucks . The fiberglass tanks may be a bit more but have a reputation for being tough. No matter if you repair or replace I wish you well with this problem. Needless to say I am empathetic (and sympathetic!) to your problem. good luck & keep us posted. Use the search button & cruise the forums, there is some great material in here.

I may try a seal on the old tank and keep it for a spare that I will never use!

[john hd]

you may find it is not the tank and simply the male end of the valve body that is clamped into the tank. they crack on occasion.

look first, you may have to make an access hole in the pan to find out.

john