Leak finding humor

I had to ask after i made a joke of this. A friend just told me that the fuel tank he installed last year leaked out 1/4 tank after he filled it up yesterday. This was a stalled project from last year so he just got back to it. He filled it yesterday and left a trail going home.
Anway i joked about putting a couple blue dye tabs in there like we used to check leak fown on toilets. But seriously. What can be used in gas for this purpose? I can usually find the gas leak source but a trail can be harder to see on all new parts.    

There's a UV dye that I've used for this. You can use it in a lot of things actually - fuel, air conditioning systems, etc. A lot of vendors make something and I suspect they're all the same. It's <$10 a bottle and a little goes a long way. You also need a black-light but you can get that on Amazon for $5-10 as well. Put in the dye, run "the thing" with the leak, then use the blacklight to trace it.

Pay close attention to the warnings. The one I used had a severe health warning notice on it...

We have been using uv dye in ac systems for years but i have not looked into using it in fuel before just starting this thread.

careful with that stuff - I have had severe skin reactions to some of those. Id wear gloves and avoid touching my face. otherwise, its probably the right stuff for the job.

If it is leaking that bad I dont think you would need any dye to see where it is leaking from.
To leave a 1/4 tank on the road it had to be leaking just filling the tank.

Next time when filling look under the trucks tank and see if it is leaking.
If not and it is full move it slowly to a clear area of the station and check again.
If still no signs of leak move the truck jurking it and look again till you find the leak.

When I fill my trucks I am looking under it just to make sure I have no leaks.
It paid off on my Flare Side rear tank as I seen a wet spot on the ground that was not there before starting the fill up. A few more times filling I was able to find that it was the fill hose. I installed a 2nd hose clamp and no more leak when filling.
Dave ----

I was more cautious than that. I said half tank it til I got back. being thin and still having fair vision I can fit in and under better than most. although straitening back out is taking longer than it used to.

Sounds like it's leaking at the stamped seam somewhere. I know on the Bullnose side mount tanks, the seam would represent approx 3/4 full mark....assuming it's the tank is not rusted all to pieces like they get here...in which case it could be leaking anywhere.

You know you're deep into the rust belt when I know not one, but TWO people that have had oil filters rust through and leak. I have replaced several oil pans over the years that rusted through and started leaking, and fuel tanks area pretty common too, but they usually rot out from the top where the salt collects on top of them.

well, it's a little more suspect than that. last year I was installing this tank brand new and got a call from my son. he was on i40 west of Knoxville driving back to his usmc base and his e4od had quit. I packed up and went to do the rescue mission. 1400 miles in two days starting at 2 pm.
this left my friend to finish and there you have it. he cannot reach or fit as I can.