How to Seal a Rusty Fuel Tank (Without Replacing It)

A rusty fuel tank means blocked filters, dead fuel pumps and a no-start classic. A new tank can cost a fortune — but a tank sealer kit will save the original for a fraction of the price.

Step 1 — Drain and clean

Remove the tank, drain all fuel and flush it out. Degrease the inside thoroughly so the sealer can bond.

Step 2 — De-rust

Pour in a rust remover/etch (part of most KBS and POR-15 tank kits), slosh it to cover every internal surface, and let it dissolve the rust. Rinse and dry completely.

Step 3 — Seal

Pour in the tank sealer, rotate the tank slowly so it coats every surface — top, bottom, baffles and seams — then drain the excess and let it cure. The result is a fuel-proof lining that locks the rust away and stops new corrosion.

Tips for a perfect job

  • Tape over the fuel-sender and outlet threads before sealing.
  • Work in a warm, dry space — moisture is the enemy during cure.
  • Don't rush the cure time before adding fuel.

A sealed tank will outlast a brand-new bare-steel replacement.

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