volvo d2-55 anode location

gcrothers

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I've searched the manuals but I cant find any reference to an anode to protect the cooling system. Am I correct in assuming there is none?

thanks
garry
 

VicS

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o.k, a bit strange though...

Not really

The fresh water circuit does not need an anode and is protected by the corrosion inhibitors in the antifreeze mixture you use in it.

The materials used and the design of the Volvo heat exchanger means that no anode is need in the salt water side of it either.
 

haydude

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Correct, there is no anode, but it does not mean it does not need one. I just had to replace the exhaust manifold at great expense because one side of it begun to leak water and it was clearly due to galvanic corrosion.

My engine had about 900 hours. The manifold was also severely clogged with carbon sooth to the point that I could just about fit my little finger through. The replacement thus removed a vibration on idle that the engine had developed with time. Clearly now I know that was because the exhaust was clogged.
 

VicS

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Correct, there is no anode, but it does not mean it does not need one. I just had to replace the exhaust manifold at great expense because one side of it begun to leak water and it was clearly due to galvanic corrosion.

exhaust manifold ? What the whole heat exchanger body ? €3000 worth?

I did not think it came in contact with salt water

Could you fit an anode in it to prevent it happening again?
 

haydude

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exhaust manifold ? What the whole heat exchanger body ? €3000 worth?

I did not think it came in contact with salt water
Could you fit an anode in it to prevent it happening again?

Yep, the exhaust manifold, that is the exhaust part attached to the back of the heat exchanger where water is mixed with exhaust and pushed down the ... "riser". About £380 just for that bit. It was severely clogged where it joins the heat exchanger and the hole formed just under all that sooth. I guess the sooth kept the area well wet even if it was before the holes where the water is injected in the manifold.

Also one of the two holes where the water is injected was totally closed by incrustations.

Now if I leave the boat for more than a few days I open the water strainer, stick a hose in it and run the engine to flush the system with fresh water. An Hozelock nozzle fits perfectly into the water intake of the Volvo Penta strainer, the suction from the engine pump keeps it tight in place. I fit a hozelock stop cock on the hose too so that I can start the engine and open the cock, run it for a few minutes than stop the engine and shut the cock.
 
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Tranona

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Anodes are only needed in heat exchangers when there are dissimilar metals in their construction and this is not the case with Volvo units. Suspect your problem started because the gasket leaked and allowed hot salt water to be sucked into the faces. Elbows have a variable life, and short life is often because the engine has not been run hard enough and allows the build up of deposits inside. You tend to get far longer life if engines are used a lot. Mine has 3500 hours on the original elbow. Alternative fabricated elbows are available for significantly less money than the OE units. Build up can be reduced by always running the engine under load, making sure it always gets up to operating temperature and cleaning it periodically.
 

VicS

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Yep, the exhaust manifold, that is the exhaust part attached to the back of the heat exchanger where water is mixed with exhaust and pushed down the ... "riser". About £380 just for that bit. It was severely clogged where it joins the heat exchanger and the hole formed just under all that sooth. I guess the sooth kept the area well wet even if it was before the holes where the water is injected in the manifold.

Also one of the two holes where the water is injected was totally closed by incrustations.

Now if I leave the boat for more than a few days I open the water strainer, stick a hose in it and run the engine to flush the system with fresh water. An Hozelock nozzle fits perfectly into the water intake of the Volvo Penta strainer, the suction from the engine pump keeps it tight in place. I fit a hozelock stop cock on the hose too so that I can start the engine and open the cock, run it for a few minutes than stop the engine and shut the cock.

Oh just the exhaust water injection elbow, not a manifold... Despite its price pretty close to being a "consumable" .

No mix of metals AFAICS so no galvanic corrosion and not I would have thought practical to protect with an anode.

A riser, by the way, is something some engines have in place of the standard injection elbow

Here's one for D1 series engines https://www.marinepartseurope.com/en/volvo-penta-explodedview-7746500-25-9785.aspx
 
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