PontiacBonnevilleClub.com

Ref: 2010 DTS case split re-sealing

Instead of using ready-made molded rubber gaskets for case split, oil pan, and oil pan bed plate, some of the Youtubers are using only RTV to fill in the entire grooves and are claiming GM recommends this.

Was this a 90’s thing and is there any advantage I’m not seeing?
I have heard of some repairs only lasting a couple years (not sure of method used).

I don't think that they're forgoing the actual gasket. They're using both to fill everything in. Gaskets are great, but can't get every nook, cranny or surface imperfection despite the best machining/manufacturing efforts. GM has had what they call "Porosity issues" when aluminum black castings (LS motors). So when resealing them, it's both the gasket and RTV.