Leak or Thread Sealant?

nU7OuxIx

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I picked up my 2021 JLUR about three weeks ago and have about 110 miles on it. I decided today to scrounge around under the vehicle with my creeper and take a look to see what's going on.

In an area where the engine meets the bell housing, I noticed an area on each side that may be a little leak or may be some sort of lubricant or thread sealant from assembly. I'm hoping that it may be thread sealant or something from assembly, because it seems to be right around where the bolts are. Plus it looks like there may be a little drain opening, where nothing is dripping from there.

Looking for an opinion on this. Normal? Something to keep an eye on? Thanks!

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Mfarr75

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So that is the rear mail seal area. I believe every Jeep made since the beginning of time either leaks, or will leak at the rear main seal. For some reason, Jeep has never figured that one out.

Now, looking at yours I don't see evidence of an oil leak. Jeep apparently was nice enough to give us a "weep hole" so we can monitor the oil leak. Otherwise you knew by a drop or two on the driveway and the used to be open area (on the 4.0 TJ anyway) between the housing and engine would be saturated with old crusty oil. Most of us just with the old TJ's ignored the issues because it's such a slow leak, and drove on for a hundred thousand miles.

I'd say you are seeing leftover gasket or thread sealant washing out the weep hole area. If it was a oil leak, it would be pretty apparent I think, and a lot greasier around the surfaces.
 
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nU7OuxIx

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So that is the rear mail seal area. I believe every Jeep made since the beginning of time either leaks, or will leak at the rear main seal. For some reason, Jeep has never figured that one out.

Now, looking at yours I don't see evidence of an oil leak. Jeep apparently was nice enough to give us a "weep hole" so we can monitor the oil leak. Otherwise you knew by a drop or two on the driveway and the used to be open area (on the 4.0 TJ anyway) between the housing and engine would be saturated with old crusty oil. Most of us just with the old TJ's ignored the issues because it's such a slow leak, and drove on for a hundred thousand miles.

I'd say you are seeing leftover gasket or thread sealant washing out the weep hole area. If it was a oil leak, it would be pretty apparent I think, and a lot greasier around the surfaces.
Phew... My other vehicle is a YJ with a 4.0 and I know about the RMS headaches... I figured with the pentastar they may had it figured out but it doesn't sound like it. My YJ is going to need a new RMS soon.

When I saw this, I thought oh man, not this again. I'm hoping that it's just thread sealant leaking out of those two bolt holes, but I guess it's something that I'm going to have to keep an eye on. Unfortunately, I am going to guess that a new RMS on the 2021 pentastar is much more involved than a YJ 4.0.

Thanks for the response and information. It's something to keep an eye on, but I'm not going to stress about it.
 

HeavyUser

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There's a few of us that have had the RMS Leak within the 10k miles on our new JLs. Keep an eye on it, if oil start to drip out of those little rubber plugs then take it in and get it fixed.
 
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nU7OuxIx

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Well, a bit of an update. After the Jeep cooled off, I went back out to take a closer look. Whatever is on the engine/bell housing doesn't smell like oil. So then I got brave and pulled one of those rubber plugs and stuck my finger in. Luckily, it didn't get stuck...

The inside was a bit greasy. I took a smell of the finger after it being in there and it smelled like grease, not oil. I pulled the dip stick out to make sure that smelled like oil and it definitely did.

I'd be interested to hear other's view on this, but it smelled and felt like grease in the little inspection hole that rubber plug was covering. Maybe they coat a layer of grease or mineral oil in there to prevent rust?
 

mwilk012

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Well, a bit of an update. After the Jeep cooled off, I went back out to take a closer look. Whatever is on the engine/bell housing doesn't smell like oil. So then I got brave and pulled one of those rubber plugs and stuck my finger in. Luckily, it didn't get stuck...

The inside was a bit greasy. I took a smell of the finger after it being in there and it smelled like grease, not oil. I pulled the dip stick out to make sure that smelled like oil and it definitely did.

I'd be interested to hear other's view on this, but it smelled and felt like grease in the little inspection hole that rubber plug was covering. Maybe they coat a layer of grease or mineral oil in there to prevent rust?
they dont.
 

mwilk012

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LOL. Yea, I bet the engineers thought about it, but then realized it will eventually be covered in oil anyway from the leak, so why bother with rust proofing!
Aluminum housings don't rust though...
 

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