Yanmar 3JH3E heat exchanger corrosion

[waterwks4me]

I have a Yanmar 3JH3E motor and have an issue with corrosion between the end caps and the cast aluminum heat exchanger/exhaust manifold. The corrosion is great enough that any repair is only a temporary fix. I won't get into WHY Yanmar made a cast aluminum heat exchanger and then married it to the exhaust manifold. Where was there brain on that one? Anyway where is the best place to purchase a new one? Anyone know if there is an aftermarket one? I have heard this engine has 3 or 4 model changes since first introduced. Wondering if one of the changes made was an upgrade to this terrible design flaw? I have read the previous posts about corrosion issues with Yanmar. Any help/advise would be greatly appreciated.

[Lepke]

I think a web search for replacement or custom heat exchanger would go a long way.
Anybody that repairs them probably has suppliers.
A company near me:
Custom & Stock Marine Heat Exchangers & Cooling Systems - Orca, WA
They do custom and stock replacement. Probably cheaper than Yanmar.
Also, I buy a lot of stuff from these guys: Quality marine products and boat parts
I know they sell them, but haven't bought one myself.