Zincs get stuck in the coolers

[RickyD]

I have been buying my engine zinks from BoatZincs.com. The zinc portion screws into the plug. In changing the 8 zincs my two engines use, one or two will unscrew when I try to take them out and and leave the pencil zinc portion behind. Is there a fix for this? Should I take the coolers apart when this happens to remove the zinc?

 

[Comodave]

I have had that happen to me too. I take the end cap off whatever cooler it is in and remove the broken anode. I have found old anodes left in the coolers from previous owners.

 

[RickyD]

I did that the first time it happened. My gear coolers are sealed though.

 

[jimdavi]

It can happen. I have one on the heat exchanger that does this sometimes. Remove the end cap and clean. You might try needle nose pliers to get it out.

 

[Comodave]

I have thought about sanding the diameter down a bit before I put them in. But that would shorten the life somewhat. However it might be worth it.

 

[porman]

What about using some kind of thread locker, or would that defeat the purpose.

 

[RickyD]

It can happen. I have one on the heat exchanger that does this sometimes. Remove the end cap and clean. You might try needle nose pliers to get it out.

I got hold of part of it with channel locks and tapped with a hammer. No good. Had to tap it in to get the new zinc in. That end cap I'm going to remove as I planned to check the exchanger bundle anyway.

 

[Spike]

I've had the same problem and was thinking about trying out https://redzincs.com/. I'd be curious to know if anyone here has used them. Seems like a great solution if they work as advertised.

 

[KnotYet]

Here's a tip that worked for me: if you need to clean the inner(coolant)side of the
HE tubes, use a short gun cleaning rod with the appropriate size metal brush.

 

[fryedaze]

My solution is to not wait so long to change zincs. Zincs are cheap. If I change at 12 months they aren't swollen and brittle. I use to check at a year and reinsert because there was plenty of zinc left.

If you snap a zinc off in the cap, you can drop it in muriatic acid and it will dissolve the zinc.

 

[Aurora53]

I was changing my zincs the other day and I had 3 of them come off as I was removing the caps. I used a shop vac with a small nozzle, I put it on the holes and the waisted zincs came right out.

fryedaze Thanks for the tip about the muriatic acid

 

[Southern Boater]

…..If you snap a zinc off in the cap, you can drop it in muriatic acid and it will dissolve the zinc.

Thanks for this tip, how long does it take to dissolve for pencil zincs? Cheers

 

[Comodave]

I was changing my zincs the other day and I had 3 of them come off as I was removing the caps. I used a shop vac with a small nozzle, I put it on the holes and the waisted zincs came right out.

fryedaze Thanks for the tip about the muriatic acid

Tried that and unfortunately it didn’t work on my aftercooler. Out of the 4 anodes the one that got broken off is the one that I can’t get the cap off…

 

[fryedaze]

Thanks for this tip, how long does it take to dissolve for pencil zincs? Cheers

Not sure. I just throw them in over night. I have spare caps I rotate through.

 

[O C Diver]

Another option is to use one size smaller anode. If your cooler takes a 3/4" pipe thread anode, use a 1/2" pipe thead anode with a bushing between 1/2" and 3/4". When you want to check or replace the anode, pull the bushing out of the cooler.

Obviously the anode will need to be replaced more frequently and you will need to confirm electrical continuity between the cooler and the anode.

Ted

 

[Pete Meisinger]

The parts need to be located and removed.

pete

 

[C lectric]

I have not had this happen but I always use large pliers or Visegrips, or if home I use the bench vise, to hold the anode and then use a wrench on the cap and firmly snug the anode into the cap.
I also coat the anode threads with a sealer like Rectorseal #5. Keeps the seawater out of the threads so the threads don't corrode and as it sets it helps to hold the anode in place. It is not a glue though.

I check the connection with an ohm meter.

 

[plittle2005]

Broken-off pencil anodes

To prevent broken-off pencil anodes, https://performancemetals.com/ makes them with a steel rod insert which supports the anode material.


They also recommend aluminum over zinc as it is more effective.


This pic is the anode removed from my Crusader 454 U-cooler after 6 months in brackish. Evidently a lot of electrical leakage in my (former) marina.


Also, although Performance Metals say they do not sell direct, I have called them and they will sell direct if asked.

 

[Hemi]

This is (was) an unfortunately common event with a yanmar engine we have in our runabout—once lodged it is very difficult to disassemble to retrieve. But they should be taken out because they have the potential to cause blockages if they start to swim in your system.
Here is the irony of why i think i have had this problem: i now believe they dislodge from the brass threaded fitting as a result of attempting to change the anode prematurely. It would appear that the first stage of how a zinc sacrificial behavior is to increase in diameter with chalk-like residue. I would start to back out the zincs for changes only to have the pencil end remain firmly lodged unable to back out of the same diameter hole for which it was inserted.
Would have never guessed that an increased maintenance schedule would have been the culprit, but have learned the hard way.

 

[Todd R]

I have been using these zincs. So far they work as advertised. I have adopted a replacement schedule every three months.

https://redzincs.com/

 

[SteveK]

If only the zinc would be inserted with reverse thread into plug

 

[lwarden]

I have not had this happen but I always use large pliers or Visegrips, or if home I use the bench vise, to hold the anode and then use a wrench on the cap and firmly snug the anode into the cap.
I also coat the anode threads with a sealer like Rectorseal #5. Keeps the seawater out of the threads so the threads don't corrode and as it sets it helps to hold the anode in place. It is not a glue though.

I check the connection with an ohm meter.

Sealing the gap between the anode and the bronze/brass cap is the trick to preventing them from falling out. Rector seal or I use a small amount of RTV right at the base between the two to seal the threads and prevent corrosion. They come out clean every time now.

 

[OldDan1943]

What about using some kind of thread locker, or would that defeat the purpose.

For some reason, I think using anything that would mess with the zinc just might reduce the effectiveness of the zinc.

 

[DDW]

I tried using Performance aluminum pencil anodes in the Cummins QSB. The caps are 1/2 NPT and the anodes are 5/8" sort of. They fit in the hole but without a lot of clearance. Unlike zinc, which kind of wastes away, the aluminum can swell up and get bigger. Had a heck of a time getting them out. I put the rest of the batch on the lathe and turned them to 1/2". Since they are roughly cast, this makes them a consistent diameter and also concentric with the threads and cap, which was haphazard at best. Will need to wait awhile for the next change to see if it worked.

 

[ssurabus]

Regarding Steve K's comment "If only the zinc would be inserted with reverse thread into plug", this approach would be somewhat helpful, but not solve the stuck/broken zinc problem. The reverse thread idea was also my exact initial thought when I first experienced stuck anodes and thought about how to address the fact that this simple job could be such a headache. The 2 modes of failure (besides leaving them in so long that they disintegrate) are:

1) The rod is stuck in the cooler, but the internal cavity threads are not fused
In this case the plug unthreads from the rod and the rod gets left behind (reverse threads potentially help here, but convert the problem to case 2)

2) The rod is stuck in the cooler AND the internal cavity threads have fused.
In this case, the plug/rod have basically become a single unit. Force from the wrench gets directly translated to torque on the zinc which breaks (generally at the shoulder where the fat part of the rod transitions to the skinnier threaded portion).

REDZn (redzincs.com) anodes prevent this by relieving the torque. The rod is held in the plug in such a way that it is allowed to rotate relative to the plug, but it is still retained which turns the plug into a pulling device (no/minimal torque transmitted to rod and linear pull - think prop-puller). Note that I'm the designer - as well as a very happy user.

 

[OldDan1943]

If you opt to leave the used zinc in the bell, might take a year for it to completely disappear.

 

[Portage_Bay]

REDZn (redzincs.com) anodes prevent this by relieving the torque. The rod is held in the plug in such a way that it is allowed to rotate relative to the plug, but it is still retained which turns the plug into a pulling device (no/minimal torque transmitted to rod and linear pull - think prop-puller). Note that I'm the designer - as well as a very happy user.

I like the mechanical concpet. However what about the electrical connection metal to be protected to plug to zinc. If the zinc can rotate in the plug do you have a good electrical connection?

 

[ssurabus]

Yes - continuity is good. Thanks for asking as it's a fundamental requirement.

 

[OldDan1943]

Perhaps an ‘easy out’’ will assist in its removal??

 

[Offshore]

Zincs

I've had a few zincs slip off and remain in the exchanger.
Mechanic said if there is no elevated running temperature, don't worry about it.