Motorad Radiator Cap Adapter 3128 - The Home Depot
Amazon.com: OEMTOOLS 27249R Radiator Adapter | Attaches to All Standard Coolant-Pressure Testers | Tests Coolant Pressure on Certain Sedans and Cross Overs with Eco-Boost Engines : Automotive
Universal Radiator Adapter Set
AFCO 80072 Radiator Inlet Adapter, -20 AN Port to -16AN
20AN Water-neck Adapters, No Welding-No Clamps required – AutoPlumb