Tim,
I'd have to disagree. It should work fine on an
oil pan, though the pan would be somewhat difficult to remove.
I use this product extensively to seal case halves when I build Porsche motors. One advantage is that it never truly hardens, so it has some give when the two parts move slightly. Additionally, it does a pretty good job with filling minor imperfections in the mating surfaces. Obviously, extended exposure to
oil is not a problem.
You can use it without a gasket if the surfaces are good. I also use it with paper gaskets on things like the
oil pump cover on 356/912 motors.
Like I said, it seals pretty well, but wont separate as easily as RTV.