Absolutely - flush the engine cooling passages. The ELC if not changed per schedule will leave a film on the metal surfaces and inhibit heat exchange. I think my mechanic filled the engines with a solution of some type and ran them to circulate then drained then filled with the ELC.I just drained all my coolant and bought 16 gal of new CAT ELC coolant to replace. Before I do that, is there any recommended maintained or things I should check out while the engines don't have coolant in them?