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.
