[FordmanT]

Originally Posted by brokenweasel I had one of those with 214k on it that was a total POS. From what I read (and experienced) the rear main seal is a 2-piece and not very good. Thats where it leaked. HOWEVER, a bunch of the vacuum lines/Crank case ventilation stuff was missing/broken. So, I ripped off a bunch of the hoses and plugged the gaping holes on the valve cover. This caused the engine to build up lots of pressure and literally pour almost a steady stream out the rear main seal. Now, assuming yours is still in good, has compression and not too much blow-by, replace the PCV valve and see what happens? The problem with oil leaks in the engine is that the oil usually sprays all over the place so its hard to pinpoint.

Don't have PCV valves, weird I know but the are just a 90* vent tube without any valve or baffle

[FordmanT]

Good thing about the 2 piece rear main is that you can replace them without removing the transmission, Just the oil pan and kill two birds with one stone. But typically a high volume leak is under pressure like by the filter adapter or sending unit.

[FordmanT]

Originally Posted by brokenweasel I had one of those with 214k on it that was a total POS. From what I read (and experienced) the rear main seal is a 2-piece and not very good. Thats where it leaked. HOWEVER, a bunch of the vacuum lines/Crank case ventilation stuff was missing/broken. So, I ripped off a bunch of the hoses and plugged the gaping holes on the valve cover. This caused the engine to build up lots of pressure and literally pour almost a steady stream out the rear main seal. Now, assuming yours is still in good, has compression and not too much blow-by, replace the PCV valve and see what happens? The problem with oil leaks in the engine is that the oil usually sprays all over the place so its hard to pinpoint.

Forgot the quick fix I had for the jeep pcv issues, especially when they start getting some blow by, is to run a small line from the 90*'s on the valve covers down along the fuel lines and just vent them externally by the crossmember

[metalenough]

the 4.0L is famous for puking oil if the pcv system is cloged or missing. they have a lot of crank case pressure. if you looked over every thing else check pcv.

[metalenough]

lol i should have read the last post, said the same thing lol

[Onemanzu]

did this get solved?

edit: sorry was running out the door when I posted. What could have happened is 1 of three things that are notorious for failing on the 4.0. All are fixable with hand tools and a jack.

The first is the rear main seal which required the motor being lifted up 2 inches off its motor mounts,
The second is the valve cover gasket is very prone to giving out especially near the back.
The third is the oil filter adapter/mount, it has an O ring that goes between the two metal pieces, this guy is a bitch to fix only because finding the right tool is difficult and getting everything to seat right is even worse.

Let me know if this issue is solved or not, I've replaced all three on my jeep and had a leak free jeep for over a year until I sold it.