Leaking XJ

I have a 1999 XJ with 75000 miles on it and it leaks like crazy. I was pretty sure it was the rear main seal so I replaced it a week ago. For about a week it was fine but now i'm blowing smoke out the rear again (just every once in a while) I'm getting really frustrated with this thing. I know a lot of guys have problems with the 4.0 leaking a little, but this is bad. If any one can give me some advice, all the people behind me on the road would sure appreciate it.

When I first got mine ('91 4.0) it was leaking like a bastard. I thought it might be the rear main and it discouraged me until we pressure washed it and saw that it was coming from the back end of the valve cover, apparently a common spot. This ended up dripping down onto the downpipe where it turns to go over the crossmember, creating a nasty smell and smoke probably similar to that which you are getting. It also made a puddle right where a rear main would so we replaced the valve cover gasket.

Cost - 8 bucks and a leak free Jeep. hellz yes!