Cooling system anodes problem

Steve1980

Hi All

I wondered if anybody has come across the problem that I have.
I have twin Yanmar 4lha-stzp 240's in my 342. The boat is kept in Fresh water on the River Thames and used in salt water very rarely. The oil cooler failed and insurance company refused to pay out due the engines cooling system had ZINC anodes fitted throughout. I have searched everywhere and can not find Magnesium anodes for the engines. Even speaking to Yanmar they say they have never supplied any and couldnt find a 3rd party that can either.
Also the engine anodes have never been removed since new in 2002 as they still have the original factory paint marks on them, I am currently trying to claim through my Surveyors insurance as this was not picked up on the pre-purchase survey a week before the cooler failed, in theory I have a boat that I shouldnt be keeping in fresh water, not to mention voiding my insurance should anything else happen....
Totally confused and gutted as I love my 342.

Liberty44140

Same situation here. I am in freshwater and the only available anodes for my Volvo diesels are zinc, not magnesium or aluminum. I just changed both engine anodes and after 10 years they both still looked brand new. My mechanic told me that in freshwater the engine anodes really are not needed, not an issue. 

This is the same with pretty much every kohler generator on this forum, only anode option is zinc. 

YYZRC

Perhaps worth reaching out to these folks?

https://martyranodes.com/products/

Handymans342

Why did the oil cooler fail???

Steve1980

I personally believe the cooler failed because it was transported down to my location in minus 7 and I think it froze, the independent insurance assessor said it was corroded because of the anodes were wrong. I argued this because there was no signs of leaks at the pre purchase sale, and then all of a sudden after the cold snap on the lorry it absolutly spewed oil out as soon as it was craned into the water. Im still arguing my insurance company and also my Surveyors insurance company since Feb this year. 
The core can not be took out as it is a sealed unit however you can see oil from more than one of the holes and for it to leak so bad makes me think it split with ice as surely corrosion would cause a pin hole and slight leak to begin and get worse over time with which would be noticeable.

Steve1980

Thanks YYZRC I have messaged them, 

Steve1980

Thanks for the feedback liberty44140, Yes mine still look fairly new just a bit crusty. I probable agree with your mechanic that they are not really needed but it gives the insurance company a way out of any potential claims I guess. 
From what I can tell the engines internal cooling is a closed system with antifreeze that runs through the heat exchanger, then it has an additional cooling which is open which is pulled from the river or sea ran through a strainer, then pumped through oil cooler and out the exhaust, there are anodes in the pump and oil cooler.

Liberty44140

The freeze damage makes more sense than corrosion/anode. Here in the US our insurance doesn’t cover freeze damage unless we hire someone to winterize and they failed. If we should have winterize and we didn’t or we goofed it, that’s on us.

Handymans342

Steve1980 said:

Thanks for the feedback liberty44140, Yes mine still look fairly new just a bit crusty. I probable agree with your mechanic that they are not really needed but it gives the insurance company a way out of any potential claims I guess. 
From what I can tell the engines internal cooling is a closed system with antifreeze that runs through the heat exchanger, then it has an additional cooling which is open which is pulled from the river or sea ran through a strainer, then pumped through oil cooler and out the exhaust, there are anodes in the pump and oil cooler.

I had the same boat and the same motors. You could cut the old cooler open and see what failed inside. 

dalek

The river water goes through the air cooler also. Worth checking. I have the 400 page manual for that engine on PDF. PM me and I will send it to you, if you want it.

Aqua_Aura

The zinc is still less noble than the metals it is protecting and given that wouldn't it still corrode before the metals around it regardless of salt or freshwater? 

Steve1980

@ Aqua_Aura I think what happens is the zinc forms a crust and then becomes totally useless
@ Dalek, thanks 

Aqua_Aura

Ah yes good point. I guess that "crust" would be more prevalent when in freshwater as there is less galvanic corrosion present to expose fresh zinc. 

Michael T

The chemistry is undeniable: you need Zinc for salt water, Aluminum for brackish (higher salinity than fresh less salinity that salt) water and Magnesium for fresh water boating. You might get by with aluminum in fresh but I would never trust zinc in fresh water.....and remember this is critically important if your boat is slipped or tied-up near other boats who may not have decent galvanic isolators or in marinas (most of which) leak varying amounts of electricity into the water. Even having a functioning Mercathode type system will not save you in these conditions as this type of system becomes less effective in water that moves and swirls. If at all possible find the closest magnesium anode to your need that you can find and modify it.

Steve1980

Thanks Michael T, I have no problem in trying to modify one, however my concern is should something catastrophic happen which we could normally claim on insurance would be declined every time because the anodes are either incorrect or modified. It amazes me that Yanmar can not supply genuine magnesium ones. Also what im angry about is that this what not mention on my pre purchase survey, the fact they had never been removed for inspection as the factory paint was still on and lined up. Had they mentioned it I could have found all this out sooner and potentially not put myself in this position. 

Michael T

@Steve1980 .....agree, absolutely. Yamaha does the same thing with their jet boats. They claim their anodes are "composite" whatever that means as they won't define what the metals are or in what percentages. Many Yamaha jet boaters have added modified anodes but fear they may be violating warranty in the event of a claim. Some jet boating friends have said they would remove them prior to a warranty inspection but this doesn't answer the obvious question - why don't these manufacturers offer alternatives to a known, potentially expensive and likely occurrence!

Grahamu

Yanmar does have magnesium anodes for their sail drives only, I have them in stock. All of the Yanmar customers (200+) we sell to are in freshwater, Great Lakes, I have never heard of an oil cooler or heat exchanger failing because of the zinc anodes. When the temperature drops to -4C  we will no longer guarantee winterizing a boat. I believe  you suffered freeze damage. Whether the boat should have been winterized before trucking is arguable, but would be standard practice here in Canada.