My bav is a 2009 model and 3 years ago I had already replaced the exhaust elbow with a stainless steel version.
Back then the exhaust outlet of the heat exchanger was already in a bad shape.
This week I finally installed a new/used heat exchanger. I had an offer for the old one to be welded but the business would not be able to guarantee success so I decided to save the €1000 (or more) and instead invest into a used exchanger from ShipOutletStore.com for €2600 which is in superb shape.
I started by removing all cooling liquid using a small pump which can be attached to a cordless drill. This made the procedure effortless without any spilling.
Next, I removed the generator belt for more space.
Then, all tubes and hoses got disconnected.
The exchanger itself is mounted using five M8 bolts, one M8 nut, and four M6 nuts. All of these came out easily.
There's just enough space to pull the exchanger out towards port side and then around the corner into the port aft cabin.
After cleaning everything thoroughly, I put the new gasket onto the motor block and assembled the new heat exchanger in reverse order.
I marked all the bolts and nuts so that I would put them into the same locations as they were. A torque meter helped me apply just the right force (I don't remember the torque values but they are noted in the engine manual).
A test run of the engine showed one small leakage around the connector of the hose leading to the boiler, which I fixed by cutting the old hose a bit before retightening it.
The old heat exchanger's exhaust outlet is in really bad shape. There is almost no sealing area left and two of the bolts are almost fully exposed, like rotten teeth.
All in all, it was a repair which I had lots of respect for but it turned out to be pretty straightforward. In the end, Murphy struck, but that's a story for a different thread which I'll start afterwards.
Bonus: Now, I have a D2-75, at least according to the sticker on the new heat exchanger. :-)
Here are some pictures of the procedure.
