Hold on! Before you whip out your dipsticks and grab the tape measure I better laydown the situation. I recently bought a 91 YJ with the 2.5 and it has been blowing oil out the breather tube on the valve cover since I got it. Judging by the puddle in the guys drive way it did alot of this for the previous owner also. I pulled the plugs and they looked perfect, so no oil in the cylinders, I removed the valve cover and cleaned all the ports in it, compression is avg. 90psi, I checked all the hoses and vacuum lines and it is still puking oil up. 3 liters each way on the trip to Edmonton. While in Edmonton I ran a piece of heater hose from the breather into a 4liter jug so I can just pour it back into the engine. 1 liter by Leduc. I got to thinking screw it, lets see what happens if I just let it run nearly dry. I just let it keep puking unti it no longer registered on the dipstick and lo and behold it stopped spitting oil up. "Of course ya dummy"you're thinking, there is no oil left to puke out. Yet the engine sounds fine no valve clattering or knocking, oil pressure is slightly higher and the temperature is running back where it should be(it has been running 30C high around 105C). If I fill it up to where the dipstick says it should be, it throws it all up again and then runs fine. I don't have a shop that I can drain it all out and put the right amount in either so I ask you 2.5 owners "How long is your dipstick?" Mine is 23 3/4" from tip to where it meets the tube. If it is too short then it is over full all the time and will puke out what it doesn't need. Let me know if I'm on the right track here. Thanks