He didn't test Navistar 6040792C1 RTV SILICONE SEALANT (also available as Motorcraft TA-31). It's used to seal the oil pan on a 7.3L Powerstroke. I've removed the pan on one and I'll tell you it was a PITA to get off. Had to drive a putty knife along the seam with a hammer to get it loose. It has to be applied to CLEAN surfaces. If you want something to STICK, give that a try.
