I've been losing oil in my Cherokee ('97 4.0L AX15 4x4). It loses at least one quart every 500 or so miles. I've never seen any drips on the ground, ever. However, I do have oil all over the back side of the engine and the transmission. I replaced the oil filter adapter o-rings and the valve cover gasket, but I still lose oil like before. I don't think I'm burning too much, because I just passed an emission inspection. Any idea what I should be checking? Rear main seal maybe? Is this something I should worry about, or should I just keep feeding it oil? I use 10w30 by the way. Thanks!
If you never have any drips of oil it is likely that you are burning it. Passing the emissions isn't the best indicator of whether you have a problem or not. It does sound like you have a rear main seal problem, but that doesn't account for the amount of oil you are using.
Few things to recommend here.
1. Take a look in the air cleaner box. Is there any oil on your air filter or in the bottom of the box? If there is, you should replace all of the CCV (crankcase ventilation) components. Two hoses and two grommets. About $45 aftermarket or at a dealer.
2. Pull all of your plugs. You can tell a LOT by how the plugs look. Take pics and post them if you want comment. Look for oil fouling.
3. A compression test is never a bad idea here. It is a good "snapshot in time" of the internal condition of the engine.
Good luck and keep us posted!
99 Cherokee, 4.0 AW4, NP242
Past Jeeps: 49 Willys, 81 Scrambler, 88 Comanche Without "data", all you have is an opinion!
Could be bad rings or valve seals but RMS seal is most likely the causing the oil down the block/trans. Mine has 190,000 and most of the valve seals were shot. I say you should do a compression test, see how bad it is and replace the pan gasket and RMS.
What about the oil filter housing? I have oil dripping off of the back of my pan - thought it was the RMS. Turns out it's the oil filter housing leaking a LOT and running back under the pan and finally dripping off.
2000 XJ - 3.5'' Lift & Skinny Mudders.
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Yes there is an adapter which has 3 o rings that seal it. They eventually start to leak, it's fairly common. Getting the bolt loose is usually the problem, there's not much room to work on it and they are on there super tight.
Yeah, I already replaced the o-rings on the filter adapter (and yeah, getting the bolt loose was a pain...way to go Chrysler). I also replaced the valve cover gasket (which was extremely simple... I'll give you that one Chrysler). It helped, but I'm still losing oil.