Keeping It Cool
by Nick Brunetti

Summer is usually the time of the year when you notice that your engines may be running a degree or two hotter than usual. Or maybe you can control the temp with the throttle: the higher the RPMs, the hotter the engines become; slow your RPMS and the engines cool. Whatever your circumstances, if you’re noticing a warming trend it’s probably time to check the heat exchangers. It could be a simple fix or it could be an expensive and involved resolution—the difference can greatly depend on whether the engine’s cooling systems have been taken care of properly or ignored until the issue becomes a serious one.

Any captain worth his salt will change the impellers on his engines on a regular schedule to keep them from failing. Replacing these little guys at the dock is vastly preferable to changing them at sea after a failure, as unexpected repairs are not only unwelcome but can also be potentially dangerous.

But there is another inevitable issue that quietly builds within the tubing and channels of the heat exchanger and cooling system of an engine. It’s called scaling. As cool water runs through the heat exchange systems it will, over time, leave salt and other mineral deposits behind. These deposits will slowly build, just like barnacles or mussels on an untreated hull. The scaling will eventually rob your heat exchangers of their ability to cool the engine’s coolant and the engine slowly begins to run hotter and hotter.

One way to help lower your engine temperature is to have the heat exchanger units flushed with a substance that helps to remove the scale along with anything else that may be clogging the tiny passages in the exchangers. Captain James Heise of Overtemp offers this type of service, stating that he regularly sees improvements between two and 10 degrees as a result of his chemical flush. “It’s an eight- to 10-hour service [for twin engines]. I also clean your saltwater cooling systems, transmission cooler and everything else in the saltwater loop,” Heise says. He recommends that a heat exchanger flush be performed every 500 hours. Heat exchanger flushes are convenient because the boat is only down for a day and never has to leave the dock.

Brian McNeal from Ace Marine also emphasizes the need for preventative maintenance. Removing the heat exchangers every two years is a part of that maintenance. McNeal states, “It would be wise to pull the coolers off every two years or 1,000 hours and have them properly cleaned.” This means removing the heat exchangers from the engines, having them manually scrubbed or cleaned in a boil or ultrasonic tank, new gaskets and O-rings installed, coolant tubes inspected and……………. (To continue reading this article in print click here) You can also subscribe to InTheBite The Magazine to enjoy more industry leading editorial. ..