Heat Exchanger Anode Question

A question for the corrosion experts here on TF

My Mainsdhip has a Yanmar 6LYA engine and ZF transmission...
While checking / changing anodes recently I found the tranny Heat Xchanger anode was broken and stub stuck in the HX...removed the HX to take home & work on it in the shop. Drilled the stub out and cleaned up threads and cleaned & flushed the raw water side.

While looking at the mounting I noticed the bracket is rubber lined and HX held on w/ hose clamps.

My question - does the HX anode need to be connected electrically to the engine / boat ground to protect the HX or only be connecetd to the HX body?

I know external hull / running gear anodes need to be grounded to protect all under water gear and wondering if the same is true for engine / tranny HX's or does each anode protect each HX independently w/o a need to tie grounds together.

Any advice and expertise apprecited..

Zinc is doing its job just fine if it makes good electrical contact with the body of the gear cooler. I think most of the time when cooler is isolated with rubber it is for protection from vibe chafing, nothing to do with galvanic activity.

Ski in NC said:

Zinc is doing its job just fine if it makes good electrical contact with the body of the gear cooler. I think most of the time when cooler is isolated with rubber it is for protection from vibe chafing, nothing to do with galvanic activity.

Click to expand...

That was my understanding about rubber...used to avoid chafe & mech wear.
My first thought was need to ground the HX...but then thought each anode protects the "cell" of disimilar metals of each HX and OK w/o need ground together.

Cell is a good way of thinking about it. As Ski notes, the zinc and the heat exchanger form a self contained unit.

David

Thanks David and Ski...confirmed my second thought...originally I figured I'd have to tie to bond but reconsidered as you stated.
Thsnks again