Harley-Davidson Liquid Cooled Service

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The High Output, Twin Cooled 103 has a complete cooling system that must be inspected as part of regular, preventive maintenance. This system is very similar to an automotive cooling system.It consists of two radiators, located in the motorcycle’s right and left side lower fairings. It has fans, a thermostat, expansion tank, pressure cap, a pump and input/output hoses.The cooling system pumps coolant around the motor’s exhaust valves, helping the engine to run cooler or not overheat. It is important to keep your radiator fins clear of road debris.

Where is the Cooling System

Use a non marring tool to remove the plastic radiator grate.Compressed air should be used to clean, both, the grate and the radiator fins on the left and right sides. Reinstall the grate. The thermostat and pump are housed beneath a plastic cover, below the voltage regulator. Remove the cover to visually inspect. Make sure there are no leaks from components or any of the corresponding hoses. Clean and reinstall this cover.

Where’s the Tank?

Access the expansion tank and pressure cap in the top of the right side lower fairing. They are in an area formerly used as a storage compartment. Carefully pry the access cover with a non marring tool to expose this area of the cooling system. The coolant level has to be checked cold, on the jiffy stand.Do not remove the pressure cap as it is not part of regular maintenance. Only a visual inspection is needed. Clean the plastic cover and carefully reinstall. It is also important to visually inspect coolant lines/hoses at the cylinder heads. Simply look for any weeping or damaged lines/fittings. Wipe down anything that you can with a clean cloth and mild cleaner if necessary.

Clean as You Go

Remember, cleaning is maintenance. When a visual inspection is all that is required; add cleaning. There is a better chance of finding a small problem, or the beginning of an issue if you are cleaning while you are inspecting.

Next Up: HD Primary Fluid Service TC 103