Mercury - Quicksilver Thermostat Housing Gasket Cooling System Seal Marine Composite 53045Q01. Overview. A good seal keeps your cooling system efficient and your engine safe. The Mercury Marine 53045Q01 Quicksilver Thermostat Housing Gasket is made for MCM and MIE GM-based V8 marine engines, ensuring a tight fit and long-lasting seal between the housing surfaces. Built from durable, heat-resistant material, it prevents coolant leaks and pressure loss that can lead to overheating. It's a small pa