Impala. Monte Carlo; 5.3L. Engine Coolant Thermostat Gasket. Engine Coolant Thermostat Housing Seal. Engine Coolant Thermostat Seal. Gasket for Engine Coolant Water Inlet. O-Ring. Thermostat Housing Gasket. Housing. hsng. Water Neck. Included with: Inlet assembly, Thermostat, Thermostat Housing, Thermostat unit, Water Inlet, Water pump assembly.