I am curious to hear the experience of others with Heat Exchanger Maintenance and After Cooler maintenance; how often performed, warning signs, etc. I've just have mine done (both heat exchangers and after cooler) at the recommendation of my trusted mechanic. My Tiara lives in salt water, and the Cummins had about 650 hours running time.
I just purchased a 1985 2700 and my mechanic told me that the heat exchange is something you can change out once it goes bad...running twin 270 crusaders w/ about 850 hours on them. wonder how much truth is in what my mechanic says...
Jim - with 650 hours on your Cummins, it was probably about time to clean your heat exchangers and aftercooler. The typical sign that they need to be cleaned is that your engines start to run warm. When the temps start creeping up, then it is time. It is not hard to do yourself.
I do a complete break down and cleaning of mine about every 2 years. Every other year, I back flush the engines to clean out any deposits.