BoatHowTovideo
Do these Anodes BLOCK up COOLING SYSTEMS ?? | Ask The Expert with NIGEL CALDER
7 June 2025 · 1 min · 1K views
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.▶ 0:00 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
More from BoatHowTo
From BoatHowTo — see the channel’s boat, crew, and every analysed video.
The Sailing Directory Newsletter
One email with the fleet's best finds — the moments, boats, and stories worth your watch time. Enter your own address to get your own copy.