BoatHowTo · video

What this video covers

Nigel Calder addresses whether aluminum anodes erode in chunks and block raw-water cooling passages.0:18 Aluminum anodes are no more prone to blocking cooling circuits than zinc anodes and are likely less so, because aluminum erodes more slowly and lasts longer.0:31 The root cause of anode fragments accumulating in heat exchangers is delayed replacement: as an anode shrinks, its surface area drops and its protective effectiveness falls with it.0:59 Calder's rule is to replace anodes when they are half consumed, not three-quarters or fully gone — at that point they are still intact enough not to break apart.Watch One critical constraint applies when switching materials: aluminum and zinc anodes cannot coexist in the same engine.0:31 Switching to aluminum requires replacing every anode simultaneously.0:31 Host Jan Attenstedt notes that the BoatHowTo diesel engine maintenance course at boathowto.com covers anode replacement, heat exchanger maintenance, and retrieving anode fragments from a heat exchanger.1:36 Replacing anodes at the half-gone mark prevents the fragmentation that blocks cooling circuits in the first place.1:05

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