How to Keep Your Cool
The owner of a 48-foot trawler requested routine engine service, including fluid samples. It didn’t take long for us to notice that the coolant in the overflow tank had a cloudy, discolored appearance. The owner had changed the coolant within the past year, but sure enough, the lab sample came back with troubling results: Salt water was finding its way into the coolant.
Why that was happening, and whether major engine work would be needed to fix the problem, is a story that starts with understanding how internal combustion engines work.
TOO HOT TO HANDLE
It is an unfortunate fact that the internal combustion engine creates a lot of unused heat. Only a little less than half of the burning fuel gets turned into useful energy. The rest just makes things hot. Engine manufacturers have gone to great lengths to figure out different ways to keep that excess heat from damaging engine components. If there is too much heat, pistons will expand and seize, oil stops being slippery, and carefully crafted metals can deform. The bigger the engine, the more heat must be removed.
The automobile industry solved this problem by taking advantage of the airflow over a fast-moving car. That
