Yanmar 4JH3E anodes???

[dougweibel]

I have a Yanmar 4JH3E with a SD-40 sail drive. I am familiar with the anode location on the sail drive leg and on my Gori propeller's hub, but I cannot find any reference to an anode on the engine itself. I have been through the engine's manual and asked my usual parts supplier. Can it really be the engine itself has no anode? Seems like there should be one in the heat exchanger at least.

Thanks for any insight you can provide.

[Dockhead]

The engine has no anode. It is designed without any unlike metal issues.

[dougweibel]

OK, Thanks. Seems improbable to me but I sure don't mind one less maintenance item to worry about.

[Dockhead]

Originally Posted by dougweibel

OK, Thanks. Seems improbable to me but I sure don't mind one less maintenance item to worry about.

You can relax about the engine and concentrate your worrying on the sail drive!

Seriously, the 4JH3 is a great engine which is exceptionally reliable. One of the best things about it is the high quality of engineering of the marinization components. The heat exchangers are particularly good, particularly well integrated with the engine, and don't have the corrosion issues which many others have.

The sail drive, however . . .

[a64pilot]

Originally Posted by dougweibel

OK, Thanks. Seems improbable to me but I sure don't mind one less maintenance item to worry about.

Me too, and I’m suspicious of that.
I know my heat exchanger is full of zinc, or it looks like zinc and foams like crazy if put in muratic acid, so I assume it’s heavily zinc plated

[kenbo]

Originally Posted by Dockhead

You can relax about the engine and concentrate your worrying on the sail drive!

Seriously, the 4JH3 is a great engine which is exceptionally reliable. One of the best things about it is the high quality of engineering of the marinization components. The heat exchangers are particularly good, particularly well integrated with the engine, and don't have the corrosion issues which many others have.

The sail drive, however . . .

Dockhead,

The 4JH3E is a good engine, a bit high revving for my taste but overall good. However, your comment about the engine not having any galvanically dissimilar metals is inaccurate.

The end caps of the heat exchanger are bronze, the body of the heat exchanger is an aluminum alloy, the bolts that hold the end caps on are steel and the tube rack is a Cu-Ni alloy. That sounds like a galvanic smorgasbord to me. I've seen quite a bit of galvanic corrosion in that area alone. Personally, I'd like to see a zinc in there but Yanmar designed in in such a way that adding one would be next to impossible. So I take both end caps off and coat the mating surfaces with Tef-Gel every 2 years when I change the coolant.

And that coolant replacement is very critical for the same reason, the engine relies on the anti-corrosion inhibitors added to the coolant.

[sailorboy1]

Originally Posted by a64pilot

Me too, and I’m suspicious of that.
I know my heat exchanger is full of zinc, or it looks like zinc and foams like crazy if put in muratic acid, so I assume it’s heavily zinc plated

not anymore

BTW - calcium carbonate (scale) with foam like heck if you put acid on it

[a64pilot]

Originally Posted by sailorboy1

not anymore



BTW - calcium carbonate (scale) with foam like heck if you put acid on it

I hope I didn’t leave it in long enough to eat away all of the zinc, after a few seconds, I figured out tiny bit of calcium that was there couldn’t be causing all of that and I pulled it out.
I won’t put acid on that tube stack anymore now that I know what I do, and that includes barnacle buster et all.

My heat exchanger has been changed, it’s newer than the engine, it had to be changed on a 500 hour engine I’m sure due to corrosion, no way was that worn out in 500 hours.

[sailorboy1]

there's low pH organic salts for calcium scale removal that wouldn't "eat" metal

BTW - I've got a 17 year old Yanmar 4JH3E with almost 2000 hours and I've never due a scale removal on the heat exchanger . My last month had a Yanmar with almost 3000 hours and again never had a scale flush of heat exchanger change out.

[Dockhead]

Originally Posted by kenbo

Dockhead,

The 4JH3E is a good engine, a bit high revving for my taste but overall good. However, your comment about the engine not having any galvanically dissimilar metals is inaccurate.. . .

Well, I didn't say it didn't have any dissimilar metals -- I said that these issues were engineered around. And I might not be right about that -- it's second hand information -- but I have never had any galvanic issues with my engine and I've heard the same from many other Yanmar owners. I had all four of the coolers (heat exchanger, oil cooler, gearbox oil cooler, turbo sea water cooled intercooler) on my engine pulled off, pressure tested, and examined at 2500 hours and they were all pristine. One data point at least.


Compare and contrast to the heat exchanger in my Kohler generator. When I first bought the boat I did not understand that it had an anode, and it took me two years to figure that out. That was all it took to wreck the heat exchanger and put sea water into the fresh water side of the Yanmar 3TNE74 Stupid operator error

[a64pilot]

Originally Posted by sailorboy1

there's low pH organic salts for calcium scale removal that wouldn't "eat" metal

BTW - I've got a 17 year old Yanmar 4JH3E with almost 2000 hours and I've never due a scale removal on the heat exchanger . My last month had a Yanmar with almost 3000 hours and again never had a scale flush of heat exchanger change out.

I’ll just take the end cap off and rod it out if needed.
It wasn’t much to taking the thing apart, pretty easy.

[dougweibel]

Originally Posted by kenbo

And that coolant replacement is very critical for the same reason, the engine relies on the anti-corrosion inhibitors added to the coolant.

OK, well there is my to-do item. Thanks!

[RobField]

Hello, I have a 4JH4E engine with an aluminum heat exchanger that has corrided badly at both end caps. The lack of anodes in the raw water side is probably the cause. I am going to modify the heat exchanger end caps to add anodes. The cost for a new heat exchanger runs from $3000 to $4000 and the repair is going to be $500 to $1000.

[boxxy]

Originally Posted by RobField

Hello, I have a 4JH4E engine with an aluminum heat exchanger that has corrided badly at both end caps. The lack of anodes in the raw water side is probably the cause. I am going to modify the heat exchanger end caps to add anodes. The cost for a new heat exchanger runs from $3000 to $4000 and the repair is going to be $500 to $1000.

Keen to know if you ended up adding anodes to the heat exchanger end caps, and what the result has been? Having same corrosion issue with my 4JH4AE.

[Ericson38]

Something's changed with Yanmar. I have a 1991 4JH2-HTE with original heat exchanger (3200 hours). I pulled it apart recently during a turbo R and R. I was shocked at how pristine the end caps were, the ends of the aluminum exhaust manifold were, and the core. No rodding needed. Paint was flaking off the end caps where they need the exchanger-manifold. Put that was all, the bevels where the O rings sit were in great shape. There are no anodes in or on this this engine, and there are three heat exchangers: 1) sea water to intercooler for, air from turbo before intake manifold, 2) transmission oil to sea water exchanger, and 3) coolant to sea water. After all three, then out the mixing T.



I used the one size thicker Yanmar O rings on the heat exchanger end caps on assembly.

I think Kenbo said it best on coolant change every 2 years, along with a look see for corrosion at the end cap-exhaust manifold interface. Also check for blockages with a bright light down the tubes (from the alternator end) with a reflection mirror on the turbo (aft) end.

Extra credit-I have drainable mufflers on this boat, so after running the engine, I drain the one for the engine (not the one for the generator). On the carboned up and rusty looking turbine wheel, I'm not sure what came first, the rust or the carbon loading. Also pulling the mixing T off the turbo exhaust outlet every two years, regardless of hours.

Turbos (IHI) for these older 4JH engines are getting harder to find in your particular application (TE/HTE/DTE/UTE).