Diesel tank gasket and sealant

[Portage_Bay]

I've got leaking fuel level sender flange to tank top on all of my tanks. What gasket material and sealant have you successfully used for similar repairs? Or what gasket material and sealant have you used on your tank inspection ports?

The tanks are steel and relatively thin gauge. The fuel level sender flanges are stainless steel.

 

[JDCAVE]

I believe the seals on my fuel tank inspection ports are a solid neoprene material. I used a sparingly thin layer of silicone—not the silicone sealant but the stuff that remains grease-like. This seems to work.

 

[Portage_Bay]

Thank you! I'll be pulling them as soon as I get some other projects under control.

 

[ghost]

If they are the old style universal kind with the terminal coming through the middle. I would often take them apart and also seal them internally like they should have been. Not sure if that is still an issue but even with new I would do it to be reliable.

Like these...

 

[SoWhat]

I used a piece of EPDM rubber roofing matl to make a gasket.(Available at HD)
Permetex sells a fuel resistant sealant. No leaks so far.

 

[Solly]

Any auto parts store should be able to steer you in the right direction and have what you need. I like Permatex stuff also.

 

[Portage_Bay]

Thanks for all the help everyone. I'll be tackling that project soon.

 

[mvweebles]

Careful with these recommendations.....EPDM and Silicon and other off-the-shelf items from a standard auto-parts-store materials may NOT be chemically compatible with diesel, though a top-mounted sender may not have much contact with diesel

Here is a chart of chemical compatabilities - Silicon and EPDM is not recommended for use with diesel. BUNA-N or Nibril gaskets are the ticket. For thread sealant, Steve D'Antonio recommends Leak-Lock, manufactured by Highside Chemical.

 

[Maerin]

Neoprene and petroleum products in general (diesel) don't play well together.

Nitrile, Buna-N, as mvweebles said. Like Vaseline with O-rings. Bad combo if the O-rings are not petroleum compatible.

Devil's in the details.

 

[Portage_Bay]

Mvweelbles & Maerin,


Thank you for the reminder re neoprene and silicon and thanks for the links.



Regarding no pressure on top mounted sender fittings. I disagree because a pressed up tank or the sloshing in rough weather will put pressure on the gasket / sealant. I do see evidence of all of the fittings leaking. Though it is not yet clear if it is the mounting flange or the "terminal in the middle" as ghost suggests.

 

[ghost]

Yup. Had a boat where the fill was higher than the sender due to how the boat sat depending on loading. Just enough pressure to seep past questionable gaskets.

 

[SoWhat]

Careful with these recommendations.....EPDM and Silicon and other off-the-shelf items from a standard auto-parts-store materials may NOT be chemically compatible with diesel, though a top-mounted sender may not have much contact with diesel

Thanks. Good catch. You're correct, EPDM not recommended.