I was told by the mechanic that my heat exchanger needs to be replaced. Does anyone have the following:
1) cost of new heat exchanger?
2) info on how to replace?
I hope to do this work myself. Thanks

Mark - On Rhapsody the 2GM is raw water cooled, so I don't have experience with replacing a heat exchanger. On the J/30 equipment page, (main menu mouse over "Market" and click on "Equipment Suppliers", scroll down and you'll see Fresh Water Cooling. Google the Sendure Heat Exchanger part number and you'll see a number of suppliers.

Bill, that is what I thought too. I think they must be talking about the mixing elbow.

Ok - That's a different question. You really should find out from the mechanic the specifics and why he came to the conclusion he reached. Check this thread on the 2GM mixing elbow.

On two different boats with different diesels (Yanmar and Universal) at about 25 years ... the cast iron exhaust elbows have rusted through...

1st symptom is "blistering" on the outside of the cast iron or partial small cracks with rust. You see the same kind of blistering on cast iron water pumps used in pools or fountains.

I'm thinking those cast iron parts just need to be changed every 25 years whether they look bad or not.

dirty sooty exhaust in cabin is very distracting. you really don't realize just how dirty boat diesel exhaust is from these engines until it fills the cabin. And instead of pushing the cooling water out it overfills the bilge. Your first thought is that the boat is burning ... but no ... just blowing "carbonized" water into the engine compartment.

Mark: Don't jump to the conclusion that your 2GM does not have a heat exchanger -- many do. If there is a Sendure heat exchanger, it will be located aft of the engine, be made of brass, be about as big as loaf of bread, and have an automotive radiator cap. They are very easy to remove. Yank it and take it to radiator shop to be boiled out and inspected. The end caps and gaskets will probably have to be replaced. While you're at it get a couple of spare zincs.

Ok here is a picture of the 2GMF on Vee Jay 2.
the red circle is around the fresh water cap. WHICH by the way is impossible [at least so far] for me to figure out how to take off. I have the feeling the motor mounts may have been replaced with higher ones by POs ... but that is just a feeling.

The fresh water pump is at the front of the engine. and the raw water pump below it feeds directly into the integrated heat exchanger which seems to be behind the fuel filter?

Have some of the boats had a 2GM or QM with an add on heat exchanger?

Yes, I have a 2GM with a Sendure heat exchanger. My documentation indicates that it delivered that way from T-P.

Once I had to yank it to take to a radiator shop when the solder joint with a mounting bracket failed; it was no big deal. Based upon that experience I recommended to Mark that he take it to radator shop to have it boiled out and inspected.

The sacrificial zinc requires annual replacement. I have replaced the end caps and gaskets twice. On the whole it has been very reliable.

Vic - I know how to fix that problem. You can borrow my scroll saw to open the clearance on the wood panel when you're back in Newport.

Mark,
The heat exchanger is easy to replace yourself. You'll have to find some where to buy it though because Sendure doesn't sell direct. 12 years ago it cost about $300. See some photos at my blog at http://sailnordicstar.blogspot.com when I changed the hoses to all. A local marine parts dealer can probably order it for you.
Rob

Bill -- the clearance problem is with the bridge deck ... it's like they force fit the engine in under it. it appears to be at least a inch higher than the 2GM in 505. You'll see it up close this summer ... a marvel of engineering. i had to add antifreeze by poking a small hose in between the cap and the fill ... and the only way you can tell the fluid level is to let it overflow.

OK ... now we know there were two options to get to fresh water cooling. I wonder if they called the version with the Sendure a 2GMF?

specific photos from Rob's nice blog:
http://sailnordicstar.blogspot.com/searc...p;max-results=7

Bob --- if you get over to the west coast give me a buzz as we go out a few times a week, and always like to have visiting j30 skippers sail with us.

thanks everyone for the very helpful information and insight. I was on the boat yesterday and it has a heat exchanger as outlined above. This looks like an after market job as it partially obscures the Yanmar tag id on front of engine. It is brass. The Good,the Bad and the ugly of having one.

Just checked the Sen-Dure website and they do not sell direct. Good news is that the part is approximately $350.

Mark, I had a 2GM20 installed in 2000, when I bought my boat in Mobile and the mechanic said that Yanmar heat exchangers "last forever". Having said that, my boat is in fresh water and not salt (he also made a comment about that also). So I hope your diagnosis was correct, I wouldn't buy one until I took the old one out and had it pressure tested at a radiator shop, like a heater core for your car, should cost about $35 to clean & test.My mechanic went on to say that all other (than Yanmar) engines used inferior hear exchangers and they only lasted a few years. Do you have a cooling problem? I also installed a temp. and oil pressure gauges when the new engine went in.

Steve, I have not had any problems with cooling. This is what I get when I have a mechanic do an engine survey. I have the feeling that they look for any and all issues where they can make a buck. I hate to say that but it does happen. I agree on trying to rehabiliate just like you would for a heater core. Thanks

So OK ... down here getting Vee Jay ready for season, installed new raw water pump because old one was leaking at seals and I didn't have energy to rebuild. But then
NO WATER out exhaust.

Tracked it back to exhaust water injector elbow that I had replaced TWO years ago ... blocked solid with soot mud. not rust, not corrosion. just a black mud. we had a hot summer here and this may have been expanded by some sort of bacteria over the last six months of sitting.

30 seconds with screwdriver to clear out. Hour and a half mechanics around that fix. Fortunately I had my foredeck guy to do the work while I just handed him the tools.

while it looks like there is a hole in the mud ... it was a solid block at least 1.5 inch deep into hole.



{Bill this post probably should be tied in to another thread ... but I couldn't find it.}

Black mud is usually a soft rust product caused by not enough oxygen to form red rust. I don't remember if it is ferrous or ferric.

interesting, this exhaust elbow was put in service April 2008. and today it was solidly blocked. although last May it was working fine during a good 4 hour run ... before lay up for the summer.

It does stay in the water during the summer. Gordon river ... sort of brackish water.

I really think there is some organic thing GROWING in my engine.

Vic - during storage to prevent this in the future you need to flush the engine cooling system with clean fresh water, then put in antifreeze with anti-corrosive properties. I usually disconnect the sea strainer and run a 2 gallon bucket of fresh water through the system with a temporary hose (including the strainer), then transfer the hose to the anti-freeze solution until it starts to come out the exhaust. You then shut down the engine and reconnect the hoses.

When you return to the boat after storage you need to remove and clean or replace (if needed) the engine zincs because the antifreeze leaves a film and coats them.

I think it's ferric (Iron III) phosphate, which is black, and organics (cyanobacteria). Flush it like Bill suggests. Soak the stuff in sodium hydroxide (Drain-o) and you've got some pricy salt water aquarium filter material, ferric oxide, which is redish. Except I expect the contaminants would kill the fish Iron III loves phosphates and so does cyanobacteria. You'll see the pink cyano causing problems in places with light, like pools, aquariums, toilts... The black cyano shows up where there's no light, like your exhaust system.

Flush, flush, flush

roger, roger ... Phosphates... like in lawn and farm fertilizer?

one of the problems here in Florida is that kind of run off in the rivers. I talked to a couple guys at the marina and this seems to be a common problem on the river if you don't run the boat periodically.

Although I did not have this problem on my O'day with a universal motor during the seven years I had it here.