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