engine advise

I am in a bind with my 91 wrangler. It has 151,000 on the engine and a bad rear main seal. I took it to the dealer today and they told me that they wouldn't fix it. Instead they wanted to give me a quote on a used engine. They said that the rings were bad and that it has blowby. I don't what blowby is or how bad it really is. The motor seems to run strong and there is no knocking. My question is can I replace the seal and be okay for awhile? Any advise is greatly appreciated.

if it ia a 4.o I-6 IT SHOULD BARELY BE BROKEN IN!!!

It is a 4.0. after looking around in this forum I am wondering if the pvc valve is bad. My air filter was full of oil about a month ago. I don't know if either problem can make the rear main go bad again if I get it fixed. A couple of people have told me that the dealer is just trying to get more money.

Your first mistake was going to the dealer, they are always looking for that extra buck. If your aircleaner was full of oil then yes, that could be an indication of excessive blowby ( worn piston rings, cylinders & valve guides ). A compression test will tell you if if this is the case. On the bright side, if you are happy with the way the engine runs and don't mind adding oil ( within reason ) then by all means have the rear main seal replaced and drive it anyway ! The 2 problems are unrelated , I would bring it to a reputable shop and NOT a dealer .

I am getting a second opinion today so I am hoping for the best.

Inline 6 will run forever if you change the oil and let it. I'd change the seal and NOT at the dealer that won't do the work you're asking them to do. Of course, the compression test mentioned earlier is not a bad idea.