Mercury - Power Steering Cooler Cooling System Component 8M0118727. Overview. There's a certain calm that settles in when your boat responds exactly the way you expect it to. A smooth turn into a tight marina slip, a steady hold on course when the afternoon chop picks up-those small moments rely on a steering system that stays cool and consistent. The Mercury 8M0118727 Power Steering Cooler plays a quiet but vital role in that feeling. You may never see it working, but you'll absolutely feel the