fixing a weeping fuel line from a full diesel tank

[rubberduck]

Hello!

Coming out of my diesel tank i have the suction line going to the heater. The tank is a very funny shape so the line to the engine and the heater are actually about at the 1/2 full to 2/3 full level.

Anyways, the seal around the suction line is weeping. I say weeping and not leaking as it is very very low but clearly diesel is coming out. I very rarely get the tank empty enough to be able to unscrew this and do a proper fix. Is there anything i could do as a stop gap to stopping the weeping or leaking for now?

Any thoughts would be great.

[model 10]

I don't think there is anything that will seal a diesel leak that is below the fluid level. I've tried fancy aerospace sealants, epoxy's etc and everything continues to weep.

[Pete7]

You need to decant the fuel and do it properly. Sorry no short cuts been there and failed with a diesel fuel tank on my landrover.

[JPA Cate]

Pete 7 has the right of it. Borrow some jerry jugs. I hope you have a small fuel tank. You'll want to give some thought to spillage as you change from tank to tank, and it might be prudent to filter the fuel into the containers. If you're finding grit or algae in the fuel, be thankful, you can go on and polish all the fuel, clean the tank, and be good to go, having dodged a fairly common bullet. Sorry to have made the job so much bigger on you....but it's a boat. :-)

Ann

[BatEng]

This is what I used to temp fix aircraft fuel tanks. Works pretty well and will last quite a while. some of the fuel tanks we used it on were even pressurized to 6-8 psi and it would hold.
I even used it on an external oil line on my motorcycle to get me home on a long trip as well.
https://www.newpig.com/pig-wet-surfa...putty/p/PTY259

Good Luck

Tony

[NYSail]

Strange your fuel lines don’t go deeper..... 1/2 to 2/3? Personally I would address that as it seems like an issue. I also agree that it’s important with fuel to do it right...... Fire sucks.

Good luck!
Greg

[rubberduck]

Thanks for the advice everyone!

The fuel lines themselfs go all the way to the bottom of the tank, its just that the are placed in to the tank well below the full mark!

[Uncle Bob]

Originally Posted by rubberduck

Thanks for the advice everyone!

The fuel lines themselfs go all the way to the bottom of the tank, its just that the are placed in to the tank well below the full mark!

I reckon most of us worked that out.

[S/V Alchemy]

Originally Posted by Pete7

You need to decant the fuel and do it properly. Sorry no short cuts been there and failed with a diesel fuel tank on my landrover.

This. Just pump it into jerry cans and do it right.

[Nightcrawler]

Possibly Silicone Rescue tape? I keep rolls of it on board. It seals to itself and withstands most any fluid and temp extremes. Had it on a water hose 75+PSI and actually forgot about it. Not sure if it will seal diesel, but I'm guessing if you get a good clean wipe on the fuel line and start winding it on itself you may get a good temp seal.

[Adrian NAMT]

Try "ER Tape". It is advertised as capable of sealing diesel & hydraulic leaks. It can also be used underwater to do that. It is a self-sealing tape that may make a permanent fix for your problem.

Google "ER Tapes" to see their products.

[Squanderbucks]

The way I read the OP first description is that the fuel line is weeping not the tank. IMO all diesel fuel tanks should have a shut off valve close if not on the tank. That way when working on the engine or fuel lines it doesn't matter how much fuel is in the tank.
If it is actually the tank that is leaking then draining all the fuel and repairing the tank is needed. Depending on what the tank is made of the the difficulty can be decided. Fiberglass is fairly easy to repair, metal usually requires removal and having someone weld in a patch.
If it is metal on a corner or seam then I would recommend having a proper metal working shop do the repair - and maybe check for other bad places before investing too much in a tank that is soon to fail in other spots.

[stormalong]

I interpret what you are saying is that the fuel line passes into the tank part way up on the side of the tank rather than from the top. If that is what you are saying you have the prime example of why ABYC rules dictate that all tank openings be on top of the tank.



Does your insurance company know this? If you had a fire that would be enough for your insurance company to deny coverage. Besides which I am sure you don't want a fire. Be glad that it's diesel, not gas.



That tank needs to be fixed or replaced. All fuel must be removed. The tank's side opening must be welded shut, either in place or removed from the boat (better choice) to be welded.



This is one of those things that, IMO must be done right.

[Seymore]

On my Yanmar 3GM30 diesel engine, there are several connections naturally in the fuel line. Each of those connections has a little soft copper crush washer inside it, to seal.

When you open a connection, that copper crush washer is a replacement item. They workharden, and if you try to reuse it, it will leak.

When you get the fuel out of the tank, open the connector and see it there's a little copper crush washer inside, to seal. If there is, replace it.

I don't have a good suggestion for a temporary fix.

[Compass790]

Originally Posted by BatEng

This is what I used to temp fix aircraft fuel tanks. Works pretty well and will last quite a while. some of the fuel tanks we used it on were even pressurized to 6-8 psi and it would hold.
I even used it on an external oil line on my motorcycle to get me home on a long trip as well.
https://www.newpig.com/pig-wet-surfa...putty/p/PTY259

Good Luck

Tony

Amazing! I'm a rough bstd but not sure I'd wanna fly in a plane you fixed the fuel tank on. No offence intended. :-) Wouldn't object to trying on diesel boat tho