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Rear Main Seal or Oil Pan leak?

44K views 37 replies 28 participants last post by  TJfreakBC 
#1 ·
I was told by one mechanic that I have a valve cover leak and rear main seal. Replaced the valve cover gasket and mechanic said that may fix it but to watch it and see. The leak continued again, few drops here and there. I figured the RMS indeed was leaking. I went to a different shop b/c they quoted me $100 cheaper to do the RMS. This mechanic didn't think it was the RMS since I only had 83,000 miles on the Jeep(??)--not sure about that reasoning. He said the valve cover was leaking and didn't think the last shop replaced it. Also said he didn't see any oil leaking from the RMS. I had them do it again, got my money back from the other shop.

The leak actually stopped for about 2 weeks. When checking my fluids, I noticed the oil was low and topped it off, maybe 1/2 quart. The leak pretty much came back the next day. Now the leak seems to be getting worse daily, leaking more oil each time.

I crawled under there and took some pics. Any thoughts on what is leaking would be helpful. I'll probably take it to a shop, mainly bc I don't have the time to work on it. I am either working or watching my 3 year old. My 3 year old is not the best helper.

2005 4.0 with 83,000 miles--I apologize ahead of time for the long post
 
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#2 ·
Mine has the same leak and looks just like yours. I also have an '05 Rubicon with 72,000 miles. I'm 99% sure its the RMS that is leaking. When you change the RMS you have to drop the oil pan and replace that gasket as well.
Mine didn't have a valve cover gasket leak but the PCV valves were leaking on the valve cover. I replaced the (2) PCV valves and the rubber seals that hold them onto the valve cover. I'm waiting until I install my lift to change the RMS and pan gasket.​
 
#6 ·
Looks like the RMS to me. The valve cover usually leaves the entire back of the block or the rear drivers-side corner covered. The RMS is a very common problem on the I-6, even on low mileage ones. It's not super-horrible to replace since it is a two piece, but at least a couple hours on the floor in the garage. I would advise against additives myself. There are a couple very small oil passages on the motor that I would be afraid would get clogged.
 
#7 ·
My RMS was replaced at 72,000 miles. It HAS to be a design flaw for something like that to go bad at such at early stage. Many on the forum here suggest to look at the valve cover gasket as the possible culprit..... lucky for me, that too was leaking on my I6, so I had them both fixed at the same time.
 
#15 ·
My oil leak ended up being the oil pressure sender . The brass elbow on it was very loose. I cleaned it up and put new thread sealer on it and was able to make one extra turn from where it originally was. Washed the bottom of the motor and not a leak to be found. Saved my self some cash and time, for now at least.
 
#20 ·
I paid $380 for parts and labor, including the oil change, and cleaning the motor up....minus the valve cover gasket, which I bought a few days earlier. I had new spark plugs in the backseat, and they went and put them in too...no charge on the bill. I think I got a decent price for everything.
 
#23 ·
I paid $380 for parts and labor, including the oil change, and cleaning the motor up....minus the valve cover gasket, which I bought a few days earlier. I had new spark plugs in the backseat, and they went and put them in too...no charge on the bill. I think I got a decent price for everything.
Ya thats seems like a pretty damn good deal.

That doesn't look half bad! :thumb: I may try that until I save the dough to change it out myself. I was under it last night and it looks like you have to drop the exhaust from the header to the muffler before you can drop the oil pan. :banghead:
Exactly why i didnt even feel like trying to look myself. Since i got a good deal on it im going to just let the mechanic do it. And replace the valve cover gasket myself after.
 
#21 ·
well, I crawled under the jeep to see exactly where it may be coming from. It wasn't the oil sending unit, definitely seemed to be the rear main seal. With a flashlight, I was able to see that it was coming right from the bottom of where it seals. I figured, it was worth a try and put some RTV around the area. So far no leaking. It may not look pretty and may just be a temporary fix, but better than dropping some cash right now.
 
#38 ·
Is there a picture of this temp fix? It seems there was but it is not showing right now...I don't have the cash or time to fix a stubborn drip after a long trip and would like to RTV around the outer to stop it from dripping after long trips..

Can someone send me the picture or repost ..thanks
 
#24 ·
i just let mine leak, theres enough mud in there to act as RTV. LOL
So far i have never had to add oil so its just a slow seepage.
 
#27 ·
I found a leak at the back of the pan too...about two or three drops every few days. In my case all of my oil pan bolts were about 1/3 turn loose. I tightened them and so far the leak seems to have stopped or reduced significantly to where its not marking the floor anymore.

Keith
 
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