My XJ has had a rear main seal leak since I bought it three months ago. Seemed like a common problem and not a difficult fix. After a lot of thread crawling, I decided to take it to a mechanic instead of doing it myself based on time. Apparently it isn't difficult, but time consuming and "oil-y".

Once the mechanic got into it, he sent my several photos of the bottom cap. It had a crack and a rust. I will include those pictures at the bottom. He told my my two options were to replace the seals and pray or to do a lower end rebuild. I told him to put the seal in and reinstall the cap. Unfortunately, the leak is in full swing again.

The mechanic said the a simple swap of the lower cap wouldn't work because the engine components have to "wear together". That would pretty much lead me to a lower end rebuild.

My question, is rebuilding the lower end really my only option?
Does the engine need to be pulled for this? If so, wouldn't rebuilding the entire engine be a consideration?

There are 100,000 miles on the engine. What a bummer.

The oil filter adapetr O rings do a really good job mimicking a RM leak. Oil blows back and drips right there. Just tossen that out there, clean it well and watch that oil filter mount really carefully before going after the RM seal.

>>> http://www.myjeepxj.com/cherokee-rep...filter-adapter

I would also fix any and all leaks above the RMS,valve cover,oil filter adapter & dist.
If u still have a leak I would get a new bottom cap,install a new fel-pro RMS & oil pan gasket and hope for the best. Let us know.

Thanks for the help thus far. I will look into all of these things ASAP!