Thread sealant on engine/stabilizer zincs

I haven't been able to find aluminum pencil anodes - even at BoatZincs.com. Instead I have gone to using magnesium in fresh water and zinc in salt water. Aluminum for the shaft and transom are readily available at BoatZincs.

Gray Dog said:

I haven't been able to find aluminum pencil anodes - even at BoatZincs.com. Instead I have gone to using magnesium in fresh water and zinc in salt water. Aluminum for the shaft and transom are readily available at BoatZincs.

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That is why the pencil anodes at Performance Metals are good. Aluminum anodes with a SS center to prevent them from breaking off.

I have used zinc anodes for years, but with my new engine, I started to do a fresh water flush after every time I return to my dock. So the anodes are in salt water when away from the dock, but then sit in fresh water between times. As such, I think aluminum makes more sense for my engine. I still use zinc for shaft and hull.

If you look at the newer cummins they have plastic end cap on there heat exchanges so no contact with the metal at all to earth out??

Anchorage said:

If you look at the newer cummins they have plastic end cap on there heat exchanges so no contact with the metal at all to earth out??

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Perhaps the galvanic currents travel through the ionic liquids, the coolant. If you put an anode in water does it corrode? If it does and its surrounded by a more noble metal must offer protection otherwise Cummins would not bother doing it.

I am in low brackish water on the creek, and I have been letting the 2 heat exchange anodes go to pieces and not replacing them. I have Sendure and the tubes and parts are nickel-copper from what I read. When I first got boat, some dummy let the water freeze and cracked a few tubes. I had to silver braze several shut on both exchangers, and that was in 1998. Been working fine. I do in the winter drain them so they sit dry for a few months If it was full salt water I would be more concerned, BUT they are originally made in 1970. AND the cruisair heatexchanger nickel copper tubing is a unit from 1971, and has never had anodes and it is in great condition, so maybe its overrated, IF your heat exchangers are more than just copper and the water is not very salty.

Yes i have asked cummins they say so long as it is in the coolant its fine they said a lot of the newer motors are running none metal end caps now

Take read here
https://www.sbmar.com/articles/myths-using-pipe-dope-threads/


shows pics with proof that teflon and pipe dope work fine

sdowney717 said:

Perhaps the galvanic currents travel through the ionic liquids, the coolant. If you put an anode in water does it corrode? If it does and its surrounded by a more noble metal must offer protection otherwise Cummins would not bother doing it.

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Non-metallic heat exchanger end caps on CAT engines use an embedded bonding strap, which completes the circuit between the anode and the heat exchanger body. If a non-metallic cap has a anode, almost certainly uses this arrangement, if it didn't the anode would be useless.

(In Kaohsiung, Taiwan)

MAYBE a decision was made, plastic caps are cheaper than brass. Let the engine owner bare the burden the cost for the brass plugs.

Yup, maybe it saves only a dime but, a bunch of dimes make up lots of money each year.

Plastic wont corrode.
Makes sense the hidden bonding strap. prove it with ohmmeter.

Nickel alloys with copper dont seem to have problems, at least for me with corrosion.

Neither of my engine oil-trans oil coolers have a place for a zinc. Maybe considered expendable. The end of one has developed a raw water weep, it has corroded the outside of the copper. But I dont see it get wet. Solder has failed I think. To take it apart, have to heat entire piece, usually the inner tube are silver brazed, so will survive that.
The ends are soldered on. So someday I will take it apart and fix it.