FWC Sacrificial Zinc Anode

[edwardc]

For those of you with FWC (or the new Moyer block with it's own zinc anode) who are thinking of pushing off replacing the sacrificial zinc anode for another year, all I can say is don't.

I did mine this spring after one season on the Chesapeake. At first, when I pulled it out, it looked completely intact, with just a little scale on the surface. But when I went to wipe the scale off, I found that what I had was not a nice cylindrical anode, but a cylinder-shaped piece of mush! Unfortunately I did not get a "before" picture, but here's a comparison with a new one after I removed the mush.

[ArtJ]

I changed mine this year and found it completely gone after a season and 1/4

Don't put off changing it. Also be careful to use 2 wrenches to remove
least the weld breaks off the exchanger.Then you really have a problem.

Best Regards

Art

[sastanley]

Oh..that must be what the little plug is on the bottom of my HX!!!

Thanks, Ed...I'll be sure to check it out!

[jhwelch]

I change my heat exchanger zinc every other oil change (at which point is is mostly eroded away by the water flow). Having it on a schedule makes it easier to remember. I have a notebook where I write down the hour meter reading for the next oil change and I underline the hour reading for zinc replacement and engine bolt retightening (over the course of time they vibrate loose, even when using lock nuts).

[old-sailer]

Ok.. good point. Can you tell me where it is and what to look for?

Picture would be really helpful.

[ILikeRust]

If you have FWC and the Moyer HX.

[TomG]

For those of you with FWC (or the new Moyer block with it's own zinc anode)

Is there a zinc in the block? I have a 2008 MMI block and have never noticed one. I'd love to check it if there is one.

[CalebD]

What Edward did not mention is what happens to your HX if all that zinc anode crap falls off inside it.
There are a few good pictures of zinc crud buildup inside a HX on this link: http://www.pbase.com/mainecruising/heat_exchanger
It can get bad enough to disrupt the raw water flow inside your HX if you let it go too long.
On one diesel engine with HX I worked on there was a sticker on the HX that said: "Check Anode Monthly" which I'd guess is way too frequent for most recreational sail boaters but yearly (annual) replacement is highly advised.
In my limited experience it is not so difficult to do the maintenance shown in the link I posted.

[edwardc]

Is there a zinc in the block? I have a 2008 MMI block and have never noticed one. I'd love to check it if there is one.

Only in the new blocks that Moyer started casting in the last year:

http://www.moyermarine.com/new_bare_block_assembly.htm

From the above link:

"...It also has...a pencil zinc for additional corrosion protection located directly in front of the water jacket side plate."

[joe_db]

Anyone ever add a zinc to a RWC engine?

[ILikeRust]

What Edward did not mention is what happens to your HX if all that zinc anode crap falls off inside it.
There are a few good pictures of zinc crud buildup inside a HX on this link: http://www.pbase.com/mainecruising/heat_exchanger

Oh goody! Another thing to worry about!!