For this and other reasons, heat exchanger end caps should be removed annually for an inspection and clean-out. Doing so is typically straightforward and well within the capabilities of a do-it-yourselfer with moderate technical skills. Replacement gaskets should be on hand (see “Gasket Case,” March 2018) because gaskets often tear or are not reusable. Be sure not to overtighten the end caps because many are conical and will crack if their fasteners are over-tensioned. Look carefully at the detritus you remove. Dead zincs and a bit of sea grass are typical, but if you see impeller parts, be sure to check the raw-water pump. Virtually every heat exchanger I open does contain some impeller parts, which often are years old and from previous impellers, so don’t be surprised if the impeller inspection yields no damage. Regardless, it should still be checked if pieces are discovered in the heat exchanger.