Yanmar anodes and lack thereof

[WillieC]

(We recently purchased a non-Albin boat but I am posting here because you're all I have!)

The boat has a Yanmar 4LH-TE 110hp, turbo with three heat exchangers, main, tranny, and engine oil (no aftercooler). Not one anode or provision for same anywhere on the engine remotely close to the raw water circuit. The engine block and head is cast iron. The header tank/exhaust manifold/main HX casting is aluminum alloy. The transmission case is also aluminum, but the oil cooler canister is cast iron. All the associated endcaps are bronze. Did I mention no anodes anywhere? Oh, the raw water pump, all bronze, bolts up to an aluminum alloy housing with bronze fittings conveying water to HX.

I find this troubling.

I know this is a stretch, most of the larger Albins have the six cylinder behemoths, and the replaced Volvo Pentas in the 25s utilize the smaller J series engines, but I value any salient advice.

There doesn't seem to be any serious deterioration of any of the various parts and pieces (I have them all liberated from the engine crevice that cruelly masquerades as the engine room.) But I believe in science and galvanic action and, as noted, I am concerned.

The best solution I can come up with is the fact that there are minuscule drain fittings on 3 of the 6 endcaps that I MAY be able to enlarge and tap for tiny pencil zincs. But what about the other three endcaps? Would they be left unprotected? I suppose all these parts are electrically connected by virtue of being bolted up to the block as well as through the construction of the tubestacks...maybe one anode would suffice. (Amazingly, this boat is fitted with a freshwater rinse fitting before the sea strainer. Maybe that, and the fact that it likely sat on its trailer for much of its existence, is why the engine isn't a quivering mass of white powder.) Due to the freshwater rinse capability, I am thinking aluminum anodes might be better.


Do any of the larger Yanmars have similar issues or did I just get lucky, and not in a good way? Where are the anodes on your Yanmars?

Thank you all for reading.

[Tree]

If it wasn’t designed with anodes and it’s made it this far - my guess is it doesn’t need them.

I previously had a Volvo AD41P in my last boat and not one anode. Not one corrosion related failure with the 15 years of ownership. My buddy has a pair of D6-310 Volvos in his cat and they only have one small anode each.

Some engines need them, some don’t. Personally I’d prefer less anodes on the yanmar as they’re always a pain in the arse to change out as they’ve typically broken off or jammed up in the housing which results in stripping parts off to get them out.

[WillieC]

Fair points all, Tree. Thank you.