Fuel tank leak 88 USA 3.2 Mondial - is it the tank?

I am starting a new thread to focus on what appears to be a fuel tank leak on the right tank on a 88 USA Mondial 3.2. Please reference the recent threads on a fuel smell and my posts here. It all started with my recently purchased 88 3.3 cab smelling gas when driving, top down.

https://www.ferrarichat.com/forum/threads/gas-smell.368789/page-2

Attached are a couple of videos and photos. The videos are with the car running and can clearly see fuel dripping from around the welds on the hole on the bottom of the tank. It only leaks when the car is running, with or without the gas cap tight which is curious as to why. You can see the dripping around the hole and it is wicking along the weld and dripping several places there.

Before I take the tank out (ouch) why does it only leak when running. With the gas cap off there is minimal pressure in the system, yet is leaking quite a bit. Shut of the motor, dry???

So where else if not the tank could it be leaking. Notice I did put a rolled up paper towel up into the hole to see if coming from the top down the tube, and no, towel remained dry.

At my old age I do not relish the tank removal, but at lest I have a 4-post lift.

Also included is a photos' of a used right tank for sale and there are looks like 5 hose connections at the top of the tanks. I am trying to determine where the go and how to access them to disconnect.

Thanks

How can I upload a video??

Jeff
ownferraribeforedie


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Sorry I cannot seem to upload a video which clearly shows the fuel dripping. I will try to post some stills.

Jeff

 

Here is a still from the video. The two red lines point to the area where the fuel drips a drop os so each second. The wavy line is where the fuel seems to wick from the hole to the second drip point.

This is so perplexing as to again why it leads with engine running, nothing when off.

I need to determine as best we can what is happening before I start start removal.

Thanks

Jeff
ownferraribeforedie.


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Lets see if the video works. Again only leaks when car is running even with gas gap off.

https://www.dropbox.com/scl/fi/8i8egxbsn8po38fik1ijq/PXL_20250919_132555581.TS.mp4?rlkey=9xjitk8nfgg8ygmaunsctwt9g&e=1&st=wj1ehxvd&dl=0

It sure looks like its coming from the welded circle and migrating along the welded seams. While running then I would assume there must be pressure building in the tank even with the cap of enough to force the fuel through the crack? As previously posted, on a 3.2 USA cab right fuel tank there are five hose nipples on the top of the tank. At least two of them might be pouring fuel back into the tank, the accumulator return, and the fuel distributor return.

From the video there is no evidence the fuel is coming from anywhere but the area in question.

Hope the video works. Thanks and who can explain this!

Jeff

 

Thanks for the tip. I will certainly look at this, as it maybe able to be applied with the tank in place. Just a bit worried that it will drip down after it is applied since leak area is on the bottom.
Jeff