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How is this NOT going to CAUSE PROBLEMS ?? 🫣 | Ask The Expert with NIGEL CALDER
December 30, 2025 · 3 min · 2K views
Finger points to corroded heat exchanger tubes
What this video covers
Nigel Calder explains why aluminum-cased aftercoolers and intercoolers on diesel engines — specifically a Caterpillar 3126B — are prone to severe galvanic corrosion, and what to do about it.▶ 0:48 The core problem: the seawater-side cooling element inside these units is cupronickel, and when cupronickel contacts an aluminum case with any moisture present, a galvanic cell forms.▶ 1:30 That cell can develop outside the zone protected by the sacrificial anode, leaving large areas of aluminum unprotected and actively corroding.▶ 1:50 On the original question about anode material, Calder confirms that aluminum anodes designed specifically for engine use are alloyed differently from the base metal and will function correctly without corroding at the same rate as the case.▶ 1:20 The critical maintenance step is periodic disassembly: remove the end caps, pull the cupronickel cooling element, clean all surfaces, inspect and replace the O-rings that electrically isolate the aluminum case from the cupronickel core, and reassemble.▶ 1:58 Intact O-rings are the key barrier against galvanic current flow between the two dissimilar metals.▶ 1:44
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