A rear main seal that is giving me fits!

Irun

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I've done many rear main seals, without issues. However, I now have one on a friends vehicle that is being obstinate. I've helped him replace it twice and it still leaks ever so slightly. I know it was installed correctly and I didn't feel any groove worn in the crank. Any suggestions on what to do next? I really wish there was some sort of option that had two sealing lips and not one! :(
 

RMETeeJay

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Gotta ask because you don't say. Have you determined that there is no oil coming down from higher up?
 
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tworley

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Ugh this is something I need to check off my list too. The rear of the pan isnt leaking, but up front near the timing chain cover is bad. I thought fel-pro would have been the recommended seal.
 
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jeepguy03

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I've replaced probably 10 Jeep 4.0L rear main seals on Jeeps I've owned as well as family/friends' Jeeps, and I still managed to screw mine up and get the oil pan seal rolled over, causing it to leak soon after. 🤦‍♂️. I thought the rear main seal was bad until I pulled the oil pan and realized my error.
 
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Irun

Irun

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I used a fel-pro and it leaked on me. Replaced it with a Mopar and its been leak free for years and many miles now. I couldn't tell the difference, but its enough of a persnickety job, I felt it was worth getting the OEM seal.
I'll be doing this soon on mine. I was strongly advised to use a Mopar rear main seal and oil pan gasket to have the best chance of success.
I honestly never even thought about a Mopar RMS. I also need to replace the one in my LJ, so I ordered two. One for myself and one for him. Thanks and I'll report back on progress! (y)
 
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Irun

Irun

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Ugh this is something I need to check off my list too. The rear of the pan isnt leaking, but up front near the timing chain cover is bad. I thought fel-pro would have been the recommended seal.
Not a hard job, but not a fun one either. Some of the bolts up front on the oil pan go into the aluminum timing cover. It's very, very common for those to get stripped! :(
 

Jamison C

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I did the RMS with the auto swap since I had everything apart. Used a felpro and it leaks. Guess I’ll try the Mopar one as well.
 
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SkylinesSuck

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Fel-Pro BS6141 is I believe the Ford 292 seal I had used before. I'd check the measurements for it though just to make sure---I'm having a tough time finding the thread that had recommended it. I'm not 100% on it being double lipped now but I think that was the reason it was recommended to me way back when. It's been a while.

I'm curious to see what they all look like compared to each other, especially the "new double lipped" FelPro meant for Jeeps and the Mopar. If I knew a RMS wouldn't leak, I'd happily pay 3x what the other costs for it.
 
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Irun

Irun

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Fel-Pro BS 40612 Rear Engine Main Seal Set https://www.amazon.com/dp/B000C2E7YQ/?tag=wranglerorg-20

Claims it's double lipped. I'll try and find the Ford one I was telling you about earlier.

After I talked to you I remembered there are in fact two different style RMS. When I did my '99, it used the style you linked to (picture below with the wings)
71rWHu7kroL._AC_SX466_.jpg

https://www.amazon.com/dp/B000C2E7YQ/?tag=wranglerorg-20


I believe the break is 2001 - 2006, where they all use this version (picture below without wings)
41bKVEj7dZL._AC_.jpg

 
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Rcroane

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Just curious....what type of oil is in the Jeep? If synthetic or blend, switch to conventional like NAPA 10W-30 first to see if that stops the leak.
 

JEEPCJTJ

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After I talked to you I remembered there are in fact two different style RMS. When I did my '99, it used the style you linked to (picture below with the wings)
View attachment 320853


I believe the break is 2001 - 2006, where they all use this version (picture below without wings)
View attachment 320854

When I clicked the link SkylinesSuck posted it said "This does not fit 2006 Jeep Wrangler" so I was wondering why it says that.