Yanmar Engine Anode

[Major_Clanger]

Recently replaced the internal anode on my Yanmar with an OEM part. Just had a thought though; the anode is zinc but (I'm assuming) the engine barrel/cases are aluminium. That being the case how can the zinc anode provide any protection since it's more noble?

Or am I missing something?

 

[Tranona]

Is this in the block or the heat exchanger? Either way there are mixed metals immersed in the seawater and the zinc is protecting the least noble of them.

 

[vyv_cox]

Recently replaced the internal anode on my Yanmar with an OEM part. Just had a thought though; the anode is zinc but (I'm assuming) the engine barrel/cases are aluminium. That being the case how can the zinc anode provide any protection since it's more noble?

Or am I missing something?

Zinc is more anodic than aluminium. The aluminium anodes now available are very clever compositions with a galvanic potential almost the same as zinc.

 

[VicS]

Recently replaced the internal anode on my Yanmar with an OEM part. Just had a thought though; the anode is zinc but (I'm assuming) the engine barrel/cases are aluminium. That being the case how can the zinc anode provide any protection since it's more noble?

Or am I missing something?

It isn't more noble Look at a galvanic series chart.

 

[Major_Clanger]

Aah, spotted my mistake. I was looking at Indium alloy/Aluminium which is less noble. Question answered........

 

[oldgit]

Much cheaper to just buy the anode alone and not the far more expensive item complete with brass fitting.
6 anodes on my 230 HP version.