[Capt Keith]

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.