Engine anode

[westhinder]

Does every marine engine have an anode? I have a Perkins Perama M30 which does not appear to have one. In which case, how is it protected against electrolysis?

 

[Cloven]

No. Many (all?) freshwater cooled engines do not have an anode such as my Yanmar 2GM20F. Don't ask me why but I'm sure someone on the forum will give us an answer.

 

[neale]

Depends upon the materials used and whether it is fresh or raw water cooled. If it is fresh water cooled there may just be one or more on the heat exchanger.

 

[Miker]

My Volvo 2010 does not have an anode. I queried this with a Volvo engineer some time ago and he said that the appropriate bits and pieces were isolated from whatever. As you may guess, I'm not up with this topic technically.

 

[twisterkai]

Not sure about the M30, but the 4108 with a Bowman heat exchanger doesn't. If you feel the need for one (on the 4108) then Bowman recommend a piece of sacrificial black iron pipe on the salt water inlet/outlet, which is just replaced every couple of years.

Maybe the M30 is the same?

 

[vyv_cox]

A freshwater cooled engine doesn't need an anode any more than your car does, because any galvanic incompatibilities within the coolant circuit are passivated by the coolant additives, either antifreeze or a suitable summer alternative.

The seawater side normally consists of the pump, heat exchanger and exhaust, usually separated by rubber hoses so galvanic corrosion is not a problem. Provided that the materials of these are resistant to seawater corrosion, they should last for a reasonable length of time.