The factory sealed hole on your 2012 Viewfinder RV black tank (part number 4339-2) is generally located on the top surface of the tank. To identify the exact location and verify if this is the source of your leak, please review the diagrams of similar holding tanks we offer: a 29-gallon and a 30-gallon RV holding tank, both measuring approximately 60" x 28" x 6 1/8". These diagrams can help you visually match your tank and pinpoint any factory sealed holes that may be leaking. If these options do not correspond to your tank, or if you need further assistance diagnosing or repairing the leak, please contact an RV plumbing professional or reach out to our customer care team for additional support.