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THERMOCURE™ - Cooling System Rust Remover & Flush | EVAPO-RUST®

This works well. Don't forget to pull the block plugs at the bottom of the water jacket every rinse. It might take several rinses. I use distilled from my dehumidifier for rinse, then actual distilled water for the final fill. With an aluminum intake, Zerex G-05 is a good HOAT coolant.