1ton87 Posted February 15, 2013 Share Posted February 15, 2013 Hi guys, I have an '87 metric ton MJ 4x4 with the 4.0l. Replaced the engine 2 years back with one out of an '88 Cherokee. Ever since it has leaked as much or more oil than the old engine used to burn internally. Usually a quart to every 10 gallons of gas or so. Had to replace the leaky oil pan before putting it in originally, and just did the gasket again last week. Drove it around a few times with no problem, and the oil read fine on the stick last night before I went to the city and back. Thought it was all better, but this morning I went out to find a puddle of oil under her again just like before, and the oil level was low. Wondering if this could be a RMS leak? How would I be able to determine if it is or not? Also, if you have any other tips for determining where exactly the oil is leaking from, that would help out. The whole undercarriage gets coated in oil so it is hard to tell, but it mainly drips from the bellhousing area. Any insights would be greatly appreciated. Link to comment Share on other sites More sharing options...
hitman72 Posted February 15, 2013 Share Posted February 15, 2013 i have been chasing a leak myself. However, mine is leaking from the front and runs all the way back (along the pan). I found the best time to find the leak was after the engine got up to normal temp and ran for about 5 miles, then get out of the truck with engine running. take a rag and wipe off the drops of oil and watch for redeveloping drops (flashlight needed). I have read here that some guys always change the RMS whenever the pan is off. This is not what i did but is good insurance i guess. Link to comment Share on other sites More sharing options...
87MJTIM Posted February 15, 2013 Share Posted February 15, 2013 Some people on CC have said to check the valve cover for the leaks. Link to comment Share on other sites More sharing options...
Keyav8r Posted February 15, 2013 Share Posted February 15, 2013 Sometimes it's hard to tell where the leak is coming from. If it appears to be from the rear of the engine, check the valve cover first. It's a lot easier to replace than the oil pan gasket and/or the rear main seal. Check the passenger side of the block for oil. If it's oily high it's probably from the valve cover gasket. If it's oily low, look at the distributor and the oil filter mount. If you eliminate those areas, then look at the oil pan and RMS. My 88 was leaking at the valve cover (at the back of the engine), at the oil filter mount and (probably) also at the distributor. I've replaced all of those gaskets & o-rings and am in the process of doing the RMS, pan gasket and timing cover seal (replacing timing chain and sprockets - a LOT of slack). I probably should have done these one at a time as that would have shown where the oil was coming from, but decided to do all of them and get it over with. Link to comment Share on other sites More sharing options...
cruiser54 Posted February 16, 2013 Share Posted February 16, 2013 ANYBODY can diagnose their own leaks. I'd be looking up ABOVE first, and VERIFYING the source of the oil leak YOURSELF. Everybody, who doesn't own or have to pay for or perform your vehicle repairs, loves to poke their noggin UNDER the Jeep and come out bearing the false bad news that your RMS is leaking. Many mechanics, friends, and good old Uncle Bob seem to enjoy telling you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it? A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight and a dim flashlight, you’re good to go on your own. Don't jump on the RMS/oil pan gasket bandwagon right off the bat. Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons. First off, the engine sits nose-up and any oil will run back to the RMS area. Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber's adage apply here. "$hit flows downhill". Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first. Revised 9-15-2012 Link to comment Share on other sites More sharing options...
1ton87 Posted February 16, 2013 Author Share Posted February 16, 2013 thanks for the tips guys. gonna try to clean it up a little today and see if my leak shows itself. starting at the top. Link to comment Share on other sites More sharing options...
cruiser54 Posted February 16, 2013 Share Posted February 16, 2013 thanks for the tips guys. gonna try to clean it up a little today and see if my leak shows itself. starting at the top. Excellent plan. You're on TOP of it. Link to comment Share on other sites More sharing options...
Comanche County Posted February 16, 2013 Share Posted February 16, 2013 Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first. Good time to switch over to the HO style too. No more upside down filter and more filter options. http://www.lunghd.com/Tech_Articles/Engine/Oil_Filter_Mount_O-Rings.htm http://www.yuccaman.com/jeep/filter.html Link to comment Share on other sites More sharing options...
neohic Posted February 16, 2013 Share Posted February 16, 2013 Good time to switch over to the HO style too. No more upside down filter and more filter options. http://www.lunghd.co...unt_O-Rings.htm http://www.yuccaman....eep/filter.html You can also just reuse the Renix 90* adapter and just swap out the threaded end: http://emeraldgreen97.wordpress.com/ When I rebuilt my engine, I just turned the adapter from the upright to a horizontal position. No issues. I didn't change out the threads, but it's on my list to do yet. Link to comment Share on other sites More sharing options...
Comanche County Posted February 16, 2013 Share Posted February 16, 2013 Exactly what I did. Link to comment Share on other sites More sharing options...
1ton87 Posted April 2, 2013 Author Share Posted April 2, 2013 got side tracked working on the ford for a few weeks. back to the mj. oil seems to be coming out too low to be the valve cover, and the other gaskets seem dry around them on the passenger side. i am thinking i'll go ahead with the rms replacement. just a little confused on how to start. the book i have says to remove the trans. & then the flywheel, doesn't mention the oil pan at all. however, i've seen on here a couple times that it can be done via the oil pan. just wondering if someone can clarify for me. i've never done one of these before. Link to comment Share on other sites More sharing options...
ComancheKid45 Posted April 2, 2013 Share Posted April 2, 2013 No need to drop the transmission. Drop the oil pan, and the back most rod bearing retainer and its exposed right there ;) The top half can be a bit tricky to swap but it can easly be done with alittle patinence. Link to comment Share on other sites More sharing options...
Geonovast Posted April 2, 2013 Share Posted April 2, 2013 Trans/flywheel must be pulled on a 2.5. You must pull the pan on a 4.0, don't need to touch the trans. Link to comment Share on other sites More sharing options...
cruiser54 Posted April 2, 2013 Share Posted April 2, 2013 I'd sure check to see if it's the OFA or dizzy gasket first before making that commitment. Link to comment Share on other sites More sharing options...
Keyav8r Posted April 3, 2013 Share Posted April 3, 2013 Search RMS replacement for some tips on doing it right. When you drop the rear main cap loosen all of the other main caps. That will provide a little more clearance to get the old top seal half out an the new one in. Do NOT use a steel drift pin, punch, or nail to drive out the old seal. If you do, you WILL scar the seal seat and have a worse leak than before. Use a brass rod and be patient. If you start getting frustrated, crawl out from under the truck and take a breather. I bought the Fel-Pro double lip seal and the blue Fel-Pro one piece oil pan gasket and highly recommend both. Check your CCV system for blockages to make sure you're not pressurizing the crankcase and forcing a leak. BTW, did I mention be patient while replacing the RMS? Link to comment Share on other sites More sharing options...
Geonovast Posted April 3, 2013 Share Posted April 3, 2013 Last RMS I did, I had someone turn the motor with a ratchet while I tapped. Helped A LOT. Link to comment Share on other sites More sharing options...
1ton87 Posted April 4, 2013 Author Share Posted April 4, 2013 got the rms put in today, took me a little bit to get the top out, but it came all in 1 peice. used loctite 518 per advice i found in another post. gonna put the oil pan back on tomorrow. looks like my felpro 1-peice is still in good shape. and we'll see how that does me. thanks for all your tips and help. Link to comment Share on other sites More sharing options...
Bornindesert Posted April 8, 2013 Share Posted April 8, 2013 Did this last weekend and only concern I have is how the pan with gasket went back in. The rear main cap has a groove which of course receives the feltpro 1 pc gasket. It seemed like it didn't want to slip into the groove, and your kinda blind working from the bottom. I'd either leave this section, the loop, dry without HiTack spray so it can find its way into the groove or exacto it from the rest of the gasket and put it in the groove first. Silicon the joint good and put the pan up with the rest of the gasket tacked in place.Good luck maybe yours will fall right into place. Mine fought me and until I run the engine I'm thinking its a 50/50 chance I got it in the groove. Link to comment Share on other sites More sharing options...
1ton87 Posted April 9, 2013 Author Share Posted April 9, 2013 been driving her around for a few days now, no puddles yet, and haven't had to add any oil. just degreased and sprayed down the engine this afternoon. still gonna keep a close eye on the dipstick and see if the engine stays clean. but my leak seems to have stopped. Link to comment Share on other sites More sharing options...
1ton87 Posted April 18, 2013 Author Share Posted April 18, 2013 oil level is still good after normal driving for 2 weeks. engine is mostly clean since my wash, just a little bit of oil still blowing out the filter on top of the rocker arm cover. any tricks for stopping that? Link to comment Share on other sites More sharing options...
cruiser54 Posted April 18, 2013 Share Posted April 18, 2013 The filler cap leaking? Remove the rubber seal. Cut a piece of bicycle inner tube to the same dimensions as the seal. Put the inner tube piece on, then the original seal. Might take a pair of pliers to twist the cap on but it gets easier over time. No more filler cap leaks. Link to comment Share on other sites More sharing options...
Keyav8r Posted April 19, 2013 Share Posted April 19, 2013 1ton87 - Did you say filter or filler? AFIK, there should be a filler cap (as Cruiser54 said) on the valve cover and two hose connections. One hose goes to the manifold to pull vapors from inside the valve cover into the manifold and one goes to the air filter box to provide clean air to replace the vapors pulled into the manifold. Link to comment Share on other sites More sharing options...
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