BD722 Single Bolt Heat Exchanger Cap Anode fitting / sealing problem

[fox1984]

Hi there, we run a beta marine BD722 diesel with an older single bolt heat exchanger on top and found the front end cap of the tube container leaking sea water.
O-Rings were exchanged, still leaking.

We also found the remains of an older sealing material (?) around the cap, that _looks_ like zinc anode material, and MAY even be a zinc anode - additionally to the pencil anode in the same end cap.

Are there any of these end caps, that have a special anode like this around at all, or is that material rather an improvised sealing material smeared around the cap earlier? We have no knowledge of previous owners' measures to seal it off...

What are we doing wrong?
Any helpful questions and remarks are more than welcome

Cheers,

 

[BabaYaga]

I have the same engine, from 2005, however on mine the pencil anode sits in the rear end cap (which has an internal divider).
Have never heard of a circular anode, Probably an attempt by the PO to seal the leak. Normally the o-ring should achieve this, provided the mating surfaces are not harmed. The o-ring seals in 3 directions, against the end cap, the tube stack and the inside of the HE housing.
Another possibility for leaking is by the centre bolt, this should have a rubber washer or a metal washer with a rubber seal at the inner circumference.

 

[BabaYaga]

Edit: Since you write ’leaking sea water’, I would rather suspect the bolt.

 

[gordmac]

Might be worth asking a Beta agent? Is that not just a badly corroded part? You could probably seal it with sealant as well as the o ring.

 

[earlybird]

Is this your end cap? Sealed by a nitrile O-ring and a Dowty washer under the bolt head.

 

[Ammonite]

That looks very odd, at least compared with the BD722 I had on a previous boat which was one of the early ones. Do you have a picture of the heat exchanger? It's almost as if part of this has come away with the end cap

 

[earlybird]

Is this it?

 

[earlybird]

Or this one up to 2002?

 

[Amlov]

Ahh, what I think you are looking at is the ring on the end of the aluminium heat exchanger. This should be left in the body of the heat exchanger when you remove the cap. I have heard of corrosion and people machining new rings, but I have also heard of a requirement to spend considerable sums on a new exchanger.
Speak to Beta, but also look out for how people have repaired their heat exchangers.

I may be wrong, but it looks like a bit of an issue to resolve.

 

[fox1984]

Ahh, what I think you are looking at is the ring on the end of the aluminium heat exchanger. This should be left in the body of the heat exchanger when you remove the cap. I have heard of corrosion and people machining new rings, but I have also heard of a requirement to spend considerable sums on a new exchanger.
Speak to Beta, but also look out for how people have repaired their heat exchangers.

I may be wrong, but it looks like a bit of an issue to resolve.

YES, thanks!

 

[fox1984]

Thanks everyone for your replies and the discussion. I believe, that this might be our heat exchanger (image attached) - OR an even older model, since on that one, there is no such aluminium piece indicated or explicitely mentioned.

We also have a discussion here: Beta Marine Owners' Group | Facebook

We are now getting a new heat exchanger, which really is the worst solution, since everything else is in splendid shape...