Ugh. That would make me very nervous... if it leaks, the labor required to fix it is enormous. Which is why I pulled the engine and changed all the gaskets at once. However, if MB dealer techs have used this technique successfully, I'd say it's worth a try, if you're careful not to use too much sealant (you don't want it falling down inside in globs that could plug the oil pump inlet screen). I would also ask them exactly what sealant they are using, and use the SAME stuff. Gasket goos are not all created equal! Some work better than others, particularly in an application with an oil bath, where there is a 1/16-1/8" gap you're trying to fill (where the composite gasket would normally reside).