Dorman 902-1999 Engine Coolant Thermostat Housing Assembly Compatible with Select Ford/Mercury Models (OE FIX)

Here's the item with the list of trucks it fits: https://www.dormanproducts.com/p-131859-902-1999.aspx I bought it on Rockauto, but Amazon also has it now: https://a.co/d/4Wn2IcL Hopefully your leak is something simple like this.