Cummins Engine Zincs

W

Woody

Well-Known Member
Nov 20, 2007
9,392
N. Wisconsin/Lk Superior
Boat Info
2005 420DA
Engines
Cummins 6CTA8.3
I put a fresh set of zincs in. These are original zincs from my '05 420DA with 673 hours on them. Boat has spent it's life in the Great Lakes fresh water. Is this typical corrosion? What do yours look like? I was expecting to see them well used, surprised that they weren't.
Zincs 673hrs.JPG
 
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Where's the pictures?
 
Maybe I can buy them from you so they can last 6 months in the Puget Sound :smt043
 
They may actually be zinc and not magnesium, which is what you would use in fresh water. Considering that the zincs have not been replaced, it is highly unlikely that your intercooler and heat exchanger have been serviced. What you need to do ASAP is have a mechanic pull your intercoolers, open them up and service and inspect them. If you don't have corrosion, it will be a miracle. If you do, the oil coolers and heat exchangers will need to be inspected also. If you wait any longer, you are risking an engine replacement. The intercooler service will cost you $3,000. The heat exchangers and oil coolers can take that bill over $10,000 IF you dont have corrosion. If all those parts need replacement, double that number. Good luck and act fast.
 
I have replaced all my zincs (11 per engine) with aluminum, along with my transom and tab anodes. I would have prefered magnesium for fresh water, but I could not find magnesium anodes for my CATs.
 
JV II said:
They may actually be zinc and not magnesium, which is what you would use in fresh water. Considering that the zincs have not been replaced, it is highly unlikely that your intercooler and heat exchanger have been serviced. What you need to do ASAP is have a mechanic pull your intercoolers, open them up and service and inspect them. If you don't have corrosion, it will be a miracle. If you do, the oil coolers and heat exchangers will need to be inspected also. If you wait any longer, you are risking an engine replacement. The intercooler service will cost you $3,000. The heat exchangers and oil coolers can take that bill over $10,000 IF you dont have corrosion. If all those parts need replacement, double that number. Good luck and act fast.
Click to expand...
Or, you could invest your own time and labor and clean them all yourself for a few hundred dollars in o-rings, grease, wooden dowels and having a radiator shop pressure test/clean the heat exchangers/oil coolers.
 
Woody said:
I put a fresh set of zincs in. These are original zincs from my '05 420DA with 673 hours on them. Boat has spent it's life in the Great Lakes fresh water. Is this typical corrosion? What do yours look like? I was expecting to see them well used, surprised that they weren't.
View attachment 44807
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Woody, yes typical for great lakes, zinc does little in fresh water.
At recommendation of several anode vendors I switched to aluminum when I bought the 360. The problem was I could only get the hull anodes. They said that the zinc pencil anodes would be ok as they are small and would not effect the performance of the hull anode. The Al hull anode works well and is lasting about 3 years. The zinc pencils looked like new after 3 years, I could see the mold seams on them, they weren't doing anything with the aluminum hull anode. Earlier this year, one of the members here found http://www.performancemetals.com/anodes/navalloy.shtml now I have Al pencils also. As you probably know, buy the anode only and reuse the brass plug. No thread dope.
A short and to the point article on why no zinc in fresh water: http://www.cruisingworld.com/how/zinc-and-aluminum-sacrificial-anodes
Good luck
 
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Larry Lonero said:
Can someone tell me where these pencil zincs are located on the Cummins 6CTA 8.3?
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Just three per engine. One on the underside of the front of the heat exchanger. One on top of the aftercooler and one at the bottom of the aftercooler.


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This is the first time I have heard aluminum for fresh water. Is this recommendation coming from the manufacturer (Cummins/Sea Ray) ?
 
Freshwater use will definitely reduce your zinc usage. I flush my engine after use with freshwater and my zincs look similar after a couple of seasons even though I run my boat in salt water. However, the state of your zincs doesn't mean that your aftercoolers are ok. 12 years without service, even in freshwater, could result in engine damage. If your aftercoolers start to leak, your engine will injest water as it runs. The air side of the aftercooler also gets coated in oil reducing its ability to cool the intake air.
 
Out of curiosity, how often can you run the Cummins in salt before changing zincs? 6 months?

 
I got mine from seaboard marine. Sbmar.com


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