Replacing Engine zincs

osd9

New Member
Oct 3, 2006
4,874
MidAtlantic
Boat Info
2003 410DA
Engines
Caterpillar 3126-TA w/ ZF 80-IV
I ordered, and received, my full set of engine zincs for the 3126-TAs.

There are 11 zins in the "kit"

CAT-3126-AnodeKit.jpg




3 for the heat exchanger, 2 for the oil cooler 5 for the aftercooler and 1 for the exhaust elbow.

During my engine survey, in December of '06, I watched the CAT tech replace them. That was approximately 90 hours and 11 months ago. I will be leaving the boat in the water and I will run the Pink AF through the raw water circuit which will be laying in there from early December '07 until March 1st, '08 when I fire them back up.

A few questions...should I replace the zincs now and let them sit in the idle engine with AF or just wait another few months and replace them for my spring commisioning.

Second....any tips from those that have done this before...

Oh...and one more thing...are all of these zincs easy to find and locate...:grin:


Thanks in advance...
 
I would replace them now. Galvanic corrosion doesn't stop just because the boat isn't running.

If your engine zincs lasted a full year, I'll be surprised. If they are totally gone or in really bad shape when you pull them out, you may want to replace them more periodically. My engine zincs only last about 4-6 months. Some of them could last a year but there are a few spots on the engine that just eat them up.
 
When the zincs were replaced by the CAT tech, they were still in excellent condition. The problem is, I don't know when they were changed before that.

Jeff, did you change them before you traded? If not, I would doubt that MM would have changed them because they only had the boat a short time....and that would have been proactive...

I guess I'll just change them now and see what they look like....

The CAT tech put little locktite on each zinc....what do you guys do?
 
I don't put loc-tite on mine and have never had a problem with them vibrating out... and if anyone would have a problem with that, it would be me. I don't think you want to have any kind of substance in the threads that could block electrical current. Not sure if loctite does that or not but it may explain why your zincs last so long. :)
 
I changed the zincs on 8/16/06. I agree that MM would not have changed them while they had the boat.
 
By the way, I always changed them in August and again during winter layup (always out of the water). Don't forget the one in the Westerbeke.

The new boat has a total of 5 (2 per main and one in the genset). Boy am I saving money!
 
Dominic,

How long zincs last depends upon a lot of variables. Caterpillar says annually, but in warm salt water in Florida, I get 6 months out of them. The Westerbeke is critical since it literally eats them up. Westerbeke says every 30 days and I get 60 days on mine.

For me, the thing about changing the zincs isn't if they are used up, but the longer you leave tme in, the harder they are to get out in one piece. Many times corrosion builds up around the sacrificial part of the annode and it will unscrew from the brass plug whan you try to remove it. If that happens, you are on a fishing expidition to get the zinc part our of the system so it won't clog heat exchangers.

On the Westerbeke, if you lose the zinc in the heat exchanger, it will clog the tubes and it has to come out. that means removing the heat exchanger end cap which sends you on a mission to find a new gasket and o-ring.

Hope that helps...........
 
I read the manual (I know a little girly), and when I changed my engine zincs, I used anti-sieze where the zinc screws into the cap, and pipe sealant wher the cap went into the engine. I hope this helps.

briman
 
Dom, I tighten the zinc into the cap dry, use a bit of teflon pipe sealant and thats it. I no longer use the locktite or the no sieze. As the others do I check and change mine 2-3 times a year.

Dave
 
Thanks for the input....

And about locating the zincs....will it be IOTTMCO (intuitively obvious to the most casual observer)?
 
Oh...one more question...the genie zinc...is this the one on the bottom of the tube and is it easy to change or do I have to jack up the genie?

thanks again.
 
The cpas are either painted red or clean bronze. There is a diagram in your manual, but they are pretty easy to find.
 
If they have been changed at least once, the caps probably are not red, but are plain brass/bronze. If the plugs are white, they are not zincs.

When you change them, put your wrench on them and tighten then slightly....just enough to move the plug. That will free up an annode in case corrosion has it bound in place. Then you should be able to remove it in tact. If you don't do it this way, you can unscrew the annode from the plug if it is corrosion bound as you remove it and that leaves you with an annode stuck down in the heat exchanger, riser or aftercooler.

My Westerbeke zinc is right on the top of the heat exchanger staring you in the face as you climb down the ladder into the engine room. All it takes is a 9/16" wrench to change it. In fact, I can access all of my zincs while standing between the engines.

Gotta love the 450DA...............
 
Bologna, hogwash and bolderdash.......Just finished replacing the zincs..well...almost finished....note to self...never do something mechanical that you've never done before on a Sunday....cussin' on a Sunday is bad (for us Christians that is)...

Did the Starboard engine first...other than fa ew stubborn zincs and a few that came off the plug, it was pretty straight forward. Took my time and finished in less than 1 hour with setup and all....then on to the devil side...the Port side... the first three in the heat exchanger...out in a flash...even the one on the bottom of the outboard side....then the one in the exhaust elbow...piece of cake...now onto the two in the tranny oil cooler....one was a little stubborn and came off the plug, but now I'm experienced with that and I maneuver the zinc out of the hole....6 down, and the last 5 in the aftercooler and I can call it a day....I do the three in the front of the engine first (aft in the bilge) and the inboard top one is stuck...crack...half of the half that was left falls in the aftercooler...OK...it's one of the top ones so I figure I'll finish up the two in the back of the aftercooler and then get back to this one....the first back one comes out fine and the onto the last one....bam...the threads are snapped inside the plug and the zinc is stuck insided the aftercooler....Alright, I'll have get into the garage and drill and easy-out this one...so, let me finish up with one in front of the engine...I drag my 51 year old bones back ontop of the engine and while I'm doing that....plop....I drop the plug with half of a zinc...somewhere....an hour later (that's not a typo) the airsep off, I finally locate the little bugger...it was hidding on top of the oil filter tucked way back in there....I gather my composure and fish out the zinc in that hole and replace that zinc....now, back to deal with last one....I tried every trick in the book and when it was all set and done, there was no way that zinc is coming out of that plug....I did manage to fish out the zinc from the aftercooler, and then I just put the plug back in without a zinc. I'll order a new plug from CAT in the morning...the aftercooler plugs are the only ones that are stainless and have an O-ring on their shoulder....I'll order some spares also....

So, a liesurely afternoon in the bilge for a 1.5 hour job took me...I don't even know for sure, but I'll peg it at 5 hours and I ain't done yet....
 
wow... must be a Cat thing. I can change the zincs in about 10 minutes on my Cummins. ;-)
 

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