Hurth transmission corrosion (I think?)

[SV Kittiwake]

The transmission on our Volvo MD2040, a Hurth has some white powdery substance where the cooling water comes in. Hopefully this image is viewable:

Is this normal or should I be worried? I'm not 100% sure how or if the previous owner has connected this to the anode - should it be?

Thanks for any help.

 

[peteK]

Looks like a water leak.

 

[RichardS]

Looks like a water leak.

It could even be water dripping onto it from above because it looks like the kind of damage caused by salt water. Presumably the oil cooler will be using fresh water loaded with anti-corrosion additive?

Richard

 

[vyv_cox]

Yes, you should be worried. It indicates a serious lack of basic maintenance. As others say, the cause is a leak of seawater, which if continued will lead to big problems. Before doing anything else find the source of the leak, just lying down looking will be enough, and fix it.

 

[captainboo]

It appears to be an external bolt on cooler similar to this:-

https://www.boatpartsandspares.co.uk/zf-hurth-gearbox-oil-cooler-30mm-5399-p.asp

In which case it should be removable allowing you to inspect properly and replace if necessary.

 

[SV Kittiwake]

Thanks everyone for the clarification. I've spent a while staring at it and can't see any water dripping onto it from above. It does sit directly below the exhaust elbow - that was rusty and clogged and I replaced it with a stainless one, so that could be the cause though annoyingly I can't really verify that now. I've cleaned it up as best I can and taken photos so I can keep an eye on it.

Can anyone tell me what the nut on the top does? Could the water be seeping out of there very slowly?

This is raw water cooled - the water comes straight from the seacock / strainer then through this then up to the engine heat exchanger- is that standard?

Thanks again everyone.

 

[captainboo]

Can anyone tell me what the nut on the top does? Could the water be seeping out of there very slowly?

This is raw water cooled - the water comes straight from the seacock / strainer then through this then up to the engine heat exchanger- is that standard?

It appears to be just a hollow box that creates a cold spot on the the side of the gearbox that helps to cool the oil on the inside. I think the top nut is just a blanking cap that allows a different location for the hose tail location depending on your setup. This may be the source of the water for the corrosion if it is leaking.

Yes the water can go straight to this then onto the heat exchanger. On my engine the raw water also goes straight to the gearbox cooler then the engine oil cooler, raw water pump then the heat exchanger.

 

[Kinsale373]

Ive got the same Engine and box on a Bene 373. Its just a metal box through which the raw water flows and provides indirect cooling ( through the wall of the adjoining gearbox. So, it can be unbolted from the gearbox without any loss of gearbox fluid as they are physically seperate units. There is some white heat conductive past between the two to assist heat transfer, I think. So if you can undo the bolts it is easy enough to take off the cooling box , strip it, clean it up and check for leaks. Its very basic and easy to work on.

Kinsale 373