Wow sorry to hear this. Potassium hydroxide is a caustic and an excellent degreaser. It comes in crystal flakes in it's dry state and is mixed with water. It will etch aluminum if left in contact and slowly dissolve it. Drain and flush it out ASAP. Not sure what it will do to the tank since it's terne coated (lead and tin) but the fuel gauge sender tube is aluminum and the fuel strainer is aluminum, so is the IP case and fuel filter head. Water is heavier than diesel so the potasium hydroxide water solution will sink to the bottom and do it's job there. You may find the bottom of the fuel sender and fuel strainer black from being etched by the caustic, probably won't harm it's operation. Is your neighbor gonna buy you a new tank and IP for your Bday present?

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
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