There are several reasons to wash your engine at least every year or two. A clean engine will run cooler than a dirty one. You’ll be more apt to tackle routine belt and hose checks and the like if you know you won’t get covered with grime every time you do so. A clean engine will also make it much easier to spot leaks and to service components. Remember to protect sensitive engine components — including the air intake, distributor, and electrical parts — with plastic bags before getting started. Use dishwashing liquid or other grease-cutting detergents and a bristle brush to scrub engine and components surfaces. Rinse thoroughly. Heavy-duty engine cleaning products are available at automotive parts stores. Follow the directions carefully. You may also have your engine professionally steam cleaned.