I have the same problem on my 92 4.9 liter Eldo. I've been giving it more and more thought lately as it seems to leak alot on the drivway. It drinks"spills" about a quart every 1000 miles or less now, more than ever and its startin to bother me because I plan on keeping my car around. Does anyone know how much the dealer for example charges to replace the oil pan gasket? Cuz I looked under the other day and it wasn't a pretty site. Autozone sells it for $22 but the labor on having it installed might be large dent in the wallet. What do you guys think?
As with any engine things need to be replaced over time. The 4.9 has a number of items that can cause oil leaks. The easiest to fix are the cooling line o-rings that attach to the oil filter adapter and the radiator, the square cut seals behind the oil filter adapter and the valve cover gaskets. The oil pressure switch/sender on the oil filter adaptor can also leak. You need to look it over closely to see where its leaking from..
In terms of replacing the oil pan gasket, it can be done and the pan will come down on the 4.9 to replace the gasket.. Mike (Scotty from Caddyinfo)
I changed one on my 92' SDV. It was simple enough, though you will probably have to saw / file one of the corners off to get it back on. If it's the original gasket, it's probablt got spacers "in built" so you can't tighten it down ant further. Since I did mine, I've had no probles and the drive is clean.