Yanmar raw water leak

[toph3r]

I discovered a seawater leak in my Yanmar and believe it to be coming from the side housing on the heat exchanger. I thought it was a crack, or maybe corrosion/rust, but now that I have it off and looking at it cleaned up, it almost looks like it was patched in the past. However I suppose that could be a trick of my eye. It is leaking from around where it is circled in the pic below. I verified to be best of my ability that is is not coming from the joint of the two case piece but water actually slowly accumulates on on the outside of this house, not really near any bolts (near the right side of the red circle below).

I am trying to find a replacement, and maybe I'll get lucky, but don't have high hopes. Curious to hear ideas for other solutions, is this something that could be welded and fixed? Minimal experience with this sort of thing.

Cheers
-Topher

 

[DGA]

It's not possibly leaking from the hose joint and running down the outside and dripping off the bottom? The bare areas with no paint sort of suggest that. Cast iron can be welded with the right TIG rod, I have had success doing that, but it could be nasty if the rust is extensive.

 

[toph3r]

I had the same thought about it leaking from the hose joint, however it does not appear to be the case. The metal tube the hose slips over looks like it is newer than the rest, so perhaps that was leaking and replaced by the previous owner. That might account for the paint wear.

Sadly even if I fill the "cup" with water in my sink, I can see wetness appear along that line that kind of looks white in the pic. So it is definitely coming through the body of the metal.

 

[DGA]

It probably isn't leaking through the sealing flange area, so the repair would be find a flat or similar shaped cast iron part, old cylinder block side or head, that can be cut to fit the rusty or porous area, cut a hole out of your part and make sure the remaining base metal is sound, and TIG weld it in. Some might say to stick weld it, TIG is better for this I think.

 

[Mitchell S Allen]

If it is indeed weeping through porosity in the casting, JB weld will most likely stop it and last for years. Thin coating inside, or out. MarineTex is another possibility.
I used JB Weld with great success in similar situations.
Mitchell

 

[Warren Holybee]

It looks like the area you circled might be a rusted bubble? if that is the case I would start be removing it, and cleaning the part to bare clean metal. Then you will see if there are small cracks or whatever to repair.

 

[toph3r]

Thanks for your guys' insights.

It probably isn't leaking through the sealing flange area, so the repair would be find a flat or similar shaped cast iron part, old cylinder block side or head, that can be cut to fit the rusty or porous area, cut a hole out of your part and make sure the remaining base metal is sound, and TIG weld it in. Some might say to stick weld it, TIG is better for this I think.

My concern here is that it looks like the seeping occurs pretty close to the bolt hole, so finding a similarly shaped piece might prove very challenging.

If it is indeed weeping through porosity in the casting, JB weld will most likely stop it and last for years. Thin coating inside, or out. MarineTex is another possibility.
I used JB Weld with great success in similar situations.
Mitchell

This is an interesting idea, it might be good enough to coat the exterior and seal it up "good enough". If I go down this route, I may have to do it on the exterior because the interior of the part isn't in the best of shape (but neither would I be after 40 years of sitting in seawater). It is proving difficult to clean with my hand wirebrush, but I am going to grab a wirebrush head for my dremel and see if I can get some better results.

It looks like the area you circled might be a rusted bubble? if that is the case I would start be removing it, and cleaning the part to bare clean metal. Then you will see if there are small cracks or whatever to repair.

I don't think it is a rusted bubble. At least when I envision that, I am thinking of paint lifting off a car or metal lawn furniture. What you are seeing here is bare metal, there is the crack along the perimeter of what you might be calling as the rust bubble. I am going to spend some time trying to clean up the inside to get more information.


Here is a picture of inside with what I have been able to clean thus far, but am going to do some more cleaning. The circle roughly corresponds to the leaky area on the outside.

 

[DGA]

My guess is that it has rusted some deep pits to the point of porosity going through. You could use JB weld with success for awhile, but without actually removing the porous metal, the rust is still active in there. JB weld is excellent stuff.
To cut out the rust and fit a new butt patch, it wouldn't have to have the same contour, just close enough, or a thick piece and sand with a 5" sander/ grinder to get it closer to shape.

 

[Mitchell S Allen]

Here's what I use these days to de-rust or remove corrosion;
Molasses, roughly mix 1 part to 10 parts water. Soak the part for a few days to a week. Rinse with water. We use a pressure washer.
This won't affect paint or damage any metal.
Another alternative is cheap white vinegar.
If it is rusted deaply into porous casting these should clean it.
We use molasses in my shop on ancient auto parts, from sheet metal panels to wheels and engine parts.
I've used JB Weld to even repair a leaky gas tank. It's lasted for years. Once it sets it can be ground or machined to shape.

 

[david_buckley]

Try this guy for parts, I sold him my 3qm30. He rebuilds and resells them and he may be able to help.
Alfred R. Holzer
- Schooner Bay Marina- Imported Motors
- Authorized Dealer for Westerbeke - Universal - Yanmar & Beta Marine Diesel Engines
www.schoonerbaymarinallc.com
90530 Pageant Rd
Bayfield, WI 54814
Phone 715.779.3266