We replaced our mixing elbow last spring. If I had the skill, I would have replaced the heat exchanger too, but I chickened out. Everything we touched, whatever was next to it broke! The 90 degree elbow coming out of our engine cooling water strainer broke and the guidance is not to put brass under the water line, but I spent two weeks looking for a bronze 90 that size with no luck, so we just keep a spare brass 90 and a spare hose in the box of spares. I also found it very helpful to purchase a selection of hose pulling tools as the hose from the mixing elbow to the muffler was very hard to remove. After we replaced the cooling water pump impeller, it leaked big time, so we sent it out to
https://depcopump.com/index.php In about a week, we got it back, with the impeller, gasket and the housing all cleaned and painted, looked just like new and hasn't leaked a drop. Later, I would like to replace all the engine hoses and especially the discharge hose from the muffler to the stern. All of the water lines in our boat are stiff and have a little engine soot on them, but I am saving that for the next owner. I did replace all the check valves on the two bilge pumps, the primary and the shower.
We have hull # 62, a late model, 1987. Fiona, named after Shreck's wife. She lives in Fly Creek in Fairhope, AL on Mobile Bay.