Experience with Por 15 tank sealant for aluminum fuel tank holding diesel?

[mforum]

I’m pretty sure I have a pin hole aluminum fuel tank leak and am debating using POR15 tank sealant.

Any thoughts on using this product or other solutions aside from “that’ll be about a thousand” for a new tank?

It seems there are varied outcomes out there from worked well for years to total failure. I’ve used the degreaser and metal prep but am having second thoughts before applying the final tank sealant product. I’m thinking to just try to apply POR 15 over a 4 to 6 inch area where I think the leak is coming from rather than the entire inside of the tank as the instructions describe to prevent large spread blistering or flaking of the sealant over the areas that are oxidized inside the thank I can’t get to because of the baffle.

Tank is 19-20 gallons on an ‘86 catalina 27. I’m pretty sure it’s coming from the deepest most forward center corner where the sediment tends to accumulate.

Thanks,

 

[Project_Mayhem]

Maybe filling the tank with a dye and welding would be a more permanent solution?

 

[dlochner]

Once the pitting and leaking starts, it will continue. The only real solutions are selling the boat and making it someone else's problem or replacing the tank. At 36 years, the tank is reaching its life expectancy.

 

[mforum]

Maybe filling the tank with a dye and welding would be a more permanent solution?

In January of 2023 I suspected it was the tank, so I pulled it. Pressurized it, checked for any exterior foam bubbles with soapy water and nothing. Then I filled it with water with a UV fluorescent dye and let it sit for several nights checking for any leaks under black light which I couldn’t find. I put the tank back thinking possibly it had leaked a little with healing through the sender gasket under a very full tank. For then next 1 and a half years or so I kept the tank level at about 1/2 to 3/4 full and no leaks. In August, I filled the tank again to near full and 2 weeks later there was about 1-2 oz of diesel in the bilge.
I’m not sure how a welder would tackle the problem as it is an old tank.

 

[Rich Stidger]

I'm with @dlochner - Replace the tank, lose the band-aids.