antiquexj

Alright, folks, let's have it. I have been reading forums/posts for about a week now. I just recently built a 1985 xj w/ 4.0L 4x4 from an 88 MJ Eliminator w/ 5-spd. from 2.8L auto. When I pulled the engine out of the MJ, I did the Valve cover gasket, oil-pan gasket and rear main.(it was sitting a while). While in the vehicle, I have replaced the Oil filter adapter O-ring. Now here is my question. I am getting a lot of oil in the rear of the engine. I mean a lot. I look top side down(Valve-cover-oil filter adapter - oil pan) When it's cold, I get nothing. When it warms up it starts leaking. After driving it a while I get a lot of blown around oil underside. I'm currently running Rotella-T in it, so I know it's not a thickness issue. I put it up on the lift with it running and could physically see it drip from the rear main(really bad). what would cause it to drip/leak like that? I am a licensed mechanic and am confident I did all the repairs properly(torqued) sealed, RTV in the corners, etc. I'm stumped. I know these things like to mark it's territory, but this is horrendous. Would the OPS unit do this? Any help or guidance would be appreciated, and thank you

B.rad

Im having same problem with my 91 XJ 4.0L. Had a leak replaced, oil pressure unit, value cover gasket, oil pan gasket, rear main seal "TWICE" because still had leak after first time. Both times followed book... soap, RTV corners, torq specs....etc etc Still have leak. Starts with a slow drip and as jeep warms up, turns into a steadly leak from behind the transmission dust cover. The second time I replaced the rear seal I noticed on my test drive when I got about 1/2 mile my oil pressure dropped from to 60 to 40 psi and it started leaking again. Not a mechanic but been wrenching on toys for over 20 years. The only thing I can think of his rear main but I cant see getting two bad ones in a row. Anyone ever heard of such a thing. Can A head gasket cause a oil leak like that???

kjc

The oil pressure sender could be leaking, but it should be fairly obvious. No offense, but is it possible the rms was installed backwards? Probably not, but i've seen it done. :/

antiquexj

Well, I am pretty sure I figured out the leak. Everything leads toward the back of the motor... everything. The pitch of the motor makes all the fluids flow backwards toward the rms. The Rms can only be installed one way. There is a notch on it that matches the main bearing that can't be mistaken. As for the oil leak, I have narrowed it down to the cylinder head between number 2-3 and 3-4 cylinder on passenger side. After the RMS install again, I steam-pressurized the engine bay, and let it run. It's a slow leak but after a week of driving it, it appears to accumulate enough oil on the back of it to lead you toward a potentially serious leak. Waiting for the money for the parts, then changing them. I just keep a gallon of 15w40 on me at all times.