Fresh Water vs Sea Water Engine

[morgantheship]

Is there a difference in the effect of Fresh Water vs Sea Water on the health or longevity of a diesel engine? The reason for my question is I am looking to purchase a used Yanmar engine and I have the choice between one that has been only used with fresh water vs one that has been used with sea water.

 

[shemandr]

Ahhh, I would take the fresh water one.

 

[n624ma]

Given a choice, fresh. That said I personally know of several raw water cooled yanmars that have spent over 25 years in salt water and are still going strong.
On a side note the fresh water cooled engines run about 40 degrees hotter than the sea water cooled engines and the engine compartment temp is noticeably higher.

 

[Don S/V ILLusion]

Without knowing how or how well the salt water cooled engine was maintained, definitely go for the fresh water one

 

[petersea]

I am just a little confused by your question, are you saying a fresh water cooled engine or a salt water cooled engine or a engine that came from fresh water use only vs. a raw salt water block cooled engine, Either way the fresh water cooled engine has the edge and is what I would purchase but if I were going to use it in salt water I would makes sure it has a closed engine block cooling and a raw water heat exchanger. What model engine and year are we talking about ?? If you are going to use in fresh water only either one would work well, just make sure to check (replace) the exhaust elbow if a salt water engine.