Heat Exchanger Zinc Broken

[dpaulo]

During my end of season maintainence I attempted to change the enging zinc from the heat exchanger. When I removed the external nut I found NO zinc shaft remaining and felt ashamed that I had left it go too long. Then when I tried to insert the new zinc I realized that the old zinc was broken off of the nut and still jammed into place. Has anyone else had the same problem and are there any suggestions as to how I might remove the broken zinc shaft? Dan Paulo, Ease Alee (hull #3)

[Richard Ad]

Did you ever resolve your zinc issue from your Oct 20, 2009 post? It's 2016, I have hull #329, 800 hours, and I'm now experiencing broken pencil zincs and sometimes unscrewed zincs from the brass bolt. I tried plumbers tape (which tested okay for continuity between the two metals) and that one broke off. I'm now using Loctite. If it breaks again I'll cut a 1/4" off the length of the next one before installing just in case it is hitting the flow divider when it is screwed in. Someone said I may need to redo my engine mounts.

[Guinevere]

The zincs are too long (even the official Universal/Westerbeke part).

Trim about 1/4" off the new one before installing or it will break off and, possibly, jam on the flow diverter as you mentioned.

No issues here since trimming all new zincs.

Bob

[KevinMc]

I had a similar issue when we bought our boat three years ago. I went to replace the pencil zinc and all that came off was the nut with the zinc still inside the HE. I removed the end cap of the HE and saw the zinc was completely gone - all that was left of the zinc was about a quarter inch plugging the hole where the nut screws to the bottom of the HE.

All I did was get a bolt, slightly smaller than the hole for the zinc in the HE, and tapped the bolt using a hammer. This forced out the small piece of the zinc which hadn't wasted away. Once the zinc (the piece as about the size of a pencil eraser) was forced out of the hole I screwed in a new zinc. I didn't bother trying to get out the small piece since I figured it would dissolve in a few months.

I now check the zinc semi annually but usually have to replace it once a year.

If you have a full length zinc stuck inside the HE - I'm at a loss.

[wolfe10]

Yes, it is IMPERATIVE that the ZN be shortened by 1/4". If not, it contacts the center "web" and breaks off. Easy work with a hack saw.

And to remove broken ZN's (a good idea, as they can restrict water flow through the passages they partially block) you will need a new end cap gasket and O ring. One bolt holding the end cap in place. Easy job and can be done with the heat exchanger in place. Certainly worth the $5 and half hour of work.

[knitchie]

I have followed these discussions about shortening the zinc for quite some time with no opinion or knowledge. This fall, the zinc broke off inside the heat exchanger, so I drained the antifreeze, and pulled the heat exchanger to clear the zinc and clean heat exchanger. This may not apply to everyone, but in my case, there is plenty of extra room for the full length of the zinc. I’ll guess that not all heat exchangers are oriented the same, so each of us should pull the end off sometime to see whether we need to reduce the length of the zinc or not.

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[wolfe10]

Yes, it appears that a full length ZN can be used in SOME heat exchangers.

BUT, how do you determine if YOURS will accommodate the full length one??

Easy if your heat exchanger end cap is off as you can see if it "two blocks" into the webbing. R & R of the end cap will require a new end gasket AND O ring (not expensive or difficult to do).

Without specific information, I would sure trim the end, as a broken ZN is not something you want lying in the bottom of the heat exchanger.

If anyone has specific PN's or info on how to identify which heat exchangers will accommodate the full length ZN, PLEASE POST.

[TBOT422]

Yep, Our HE is made the same with an offset location of the zinc. My guess is that at some point in time, the manufacturer 'upgraded' the HE to fix this problem. Older models need to be trimmed and newer ones won't. How to guess? Check to see if the zinc lug is off center. How to tell for sure? Pull the end cap and view the inside of the HE with a small mirror. Replace with new gasket and O-Ring.

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[Monty]

I am dealing with this issue, and as usual, the owner's web site has been a huge help; thank you all for the past posts.

Does anyone use a sealant on the end gasket/end cap unit? I have evidence of past leaks, albeit minor, in the form of blue/green stains on both ends. I can't tell if a sealant was used in the past or not.

Thanks again for all the support.

[russp]

Hi Steve,

I don't know if this is recommended or not, but last time I opened up the hex and reassembled it I had a little weep at the gasket so I took it off and put some aviation gasket goo on it, has been watertight since. It may result in destruction of the gasket next time I take the hex apart to clean it but I will have to live with it.

I am fortunate in that Avalon is docked on a jetty near a hose so everytime we go out now I give her a fresh water flush through the cooling system so the only time the internals see salt is when were are out sailing. Hoping the raw water pump seals and hex last longer, and the anode dissolves much more slowly, but then again maybe isn't protecting what it is supposed to protect, I will find out in time!