I discovered this weekend that my Mark is leaking oil from behind the oil filter. There is a gasket behind the oil filter housing that is where the oil is coming from. Has anyone had to change this before and how difficult is it to change.

Sounds like the infamous oil filter adaptor gasket. Luckily, I have not had the pleasure to experience this repair, but the repair difficulty level is inversely proportional to your mechanical expertise. ;)

the repair difficulty level is inversely proportional to your mechanical expertise. ;)
that's easy to say!:N

Have a look here: http://www.lincolnvscadillac.com/showthread.php?t=2433

Fixed it last nite. Took about two hours and it was messy.

Fixed it last nite. Took about two hours and it was messy.
yeah, i ahve fixed it....a pain but hey did you notice the differance between the old and the new one........factory flaw......i don't know, but all the old ones are flat where the new is raised....