Originally Posted by Cigatoo
“The big plate zincs on the transom CANNOT protect the heat exchanger.”
I was told by American Diesel to be sure that the heat exchanger was grounded to the block / bonding system on my 135. I was wondering if that would eliminate the need for a zinc. Obviously will keep a new zinc in the Heat Exchanger but wondered what the effect would be. Boat is new to us and on the hard so haven’t had a chance to monitor results or changes.
No, it will not eliminate the need for the pencil zinc/electrode in the heat exchanger. The ground through the engine block won't hurt but it cannot replace the dedicated pencil zinc. Same for any other interior item such as seastrainers, gear oil coolers. SOme gear oil coolers may not have a zinc but the better ones do. Be cautious with the zincless units as they fail much more frequently than those with a zinc unless of course the zinc is not changed enough.
Once the boat goes back in the water check that zinc as I described untill you KNOW what the interval is.
Just another note is when checking that eroded zinc use a small wire brush to abrade away loose stuff. There will be some and it can look like there is a lot more electrode remaining than there really is.