What is this oil leak?

[vito2772]

Hello all,

So, recently upon looking in the driveway, I saw a few oil drips beneath the jeep. I crawl under, and I can see some (what I think to be engine) oil dripping from the front of the skid plate, through one of the holes. I look on the skid, and see a pool of oil, and some oil on the transmission above it At first, I wasn't sure where the oil was coming from maybe the rear main seal, but then I followed some oil back up the side of the transmission and saw a bunch of oil sprayed onto my block around the oil filter. Oil filter was quite loose. Got at least a full turn out of it, and then gave it a bit more with the oil filter wrench. Upon seeing the oil leaking from there, my thought was that the oil was dripping down the side of the transmission, and as I was driving, the wind was carrying the oil back onto my skid plate, leading to it collect, and finally dripping once I noticed it.

But, I see some oil on the bolts facing upwards by the transmission, shown in the picture. What is this piece with the bolts facing towards the sky? Could engine oil even be coming from this location? I'm just hoping the oil was coming from my oil filter as I described, but I'm just wondering what else it could be.

I'm pretty sure it is engine oil, but it could be transmission fluid (it is black and looks like engine oil, but I could be wrong). I don't see any oil coming from in-between the engine and the transmission as if it was the rear main seal. Any insight on to what those bolts are attached to, and if my hypothesis seems reasonable would be greatly appreciated.

 

[cpwolf]

I can only say what I would do.

1. Hand tighten the oil filter, you don’t want to crank it. My learning always was you don’t want it stuck, and more importantly you don’t want to bind the built in gasket.

2. Spray it all down with degreaser.

3. Hose it all off and get it spotless.

4. Make sure your oil is topped off (maybe do this step 2, don’t start til you check the level.

Give it a week.

It’s very possible that would spray everywhere. Visible oil coming from filter, filter is very loose, fix that and see where you sit. Don’t go over doing things unless you have to.

If you are concerned you can check your trans fluids too.

 

[vito2772]

I can only say what I would do.

1. Hand tighten the oil filter, you don’t want to crank it. My learning always was you don’t want it stuck, and more importantly you don’t want to bind the built in gasket.

2. Spray it all down with degreaser.

3. Hose it all off and get it spotless.

4. Make sure your oil is topped off (maybe do this step 2, don’t start til you check the level.

Give it a week.

It’s very possible that would spray everywhere. Visible oil coming from filter, filter is very loose, fix that and see where you sit. Don’t go over doing things unless you have to.

If you are concerned you can check your trans fluids too.

Thanks for the reply. Yes, that is my plan, I'm gonna clean it real well and just keep an eye on it for now. Last time I did an oil change, I hand tightened it and it seems maybe vibrations backed it out a little. Then again, I probably didn't snug it enough by hand.

 

[WallyWest]

I mean, sounds like you found it. Personally I tighten the filter by hand until I can't get any further, then put a wrench on it and give it about a 1/4 turn more. It's really something you just have to get a feel for. Then after driving it a few times check it to make sure it's still tight.

In general oil dripping down from a slow leak around the engine isn't going to make it back to the skid plate. I'm getting ready to replace my valve cover gasket because mine leaks at the very back of the engine. It keeps bottom of the oil pan wet, but that's about it. And I would certainly hope your transmission fluid isn't black.

 

[vito2772]

I am pretty sure it is the rear main seal since it seemed to drip the tip of my transmission right next to my oil pan.

I switched to high mileage conventional 10-30w in hopes of giving life back to the seal, but my skid plate is still dripping. See in the pictures below.

It doesn't seem to be dripping down in between the oil pan and transmission like most rms leak pictures I see. It seems it is coming from the other side of that plate on the tip of the transmission, where the slot is (looking from the bottom up). My theory is that it is dripping from up there, and coming to the tip of the transmission and blowing back into the skid plate wear it collects and drips. When I'm parked it flat it, a couple drips will come from the pointy tip. When I'm parked on an angle it will come from there, as well as through the holes of the skid plate where it blows back and collects.

It is definitely engine oil, not transmission fluid. Just wanted others opinions on whether the location of the oil drop source is a rms leak or something else.

No oil on the back of the block either.

 

[vito2772]

Update. I replaced the rms many months ago, back in September. Ever since then, the tip of the transmission has been dry. However, it kept dripping from the skid plate for months. I thought maybe some oil was leaking out of my oil filter or that area, and then blowing back into the skid plate. I have been trying to track where this oil was coming from for so long.

The strange thing was that the oil dripping from the skid was clean engine oil, while (after many miles after rms change), the oil on my dip stick was black. But it kept coming and kept dripping consistently up until last week. Stopped dripping, its all dry, all my fluids are good. Haven't lost any engine oil. I guess this was clean oil from my few changes to high mileage oil in attempt to stop rms leak before changing. And it took months for it all of it to work its way out.

Glad my drip finally stopped, never thought it would take that long for oil throw upwards to work its way out.

 

[Jerry Bransford]

Often replacing the RMS can be avoided by simply changing to a High Mileage conventional engine oil like from Pennzoil. High Mileage engine oils contain seal restorative additives that can restore the RMS back so it stops leaking. Doing only that cured a major RMS leak in my daily driver BMW which I tried after being quoted nearly $2k to replace its RMS.

 

[RussTJ]

Often replacing the RMS can be avoided by simply changing to a High Mileage conventional engine oil like from Pennzoil. High Mileage engine oils contain seal restorative additives that can restore the RMS back so it stops leaking. Doing only that cured a major RMS leak in my daily driver BMW which I tried after being quoted nearly $2k to replace its RMS.

I'm curious if synthetic oil would have the same properties to help with this issue?

 

[Jerry Bransford]

I'm curious if synthetic oil would have the same properties to help with this issue?

Some synthetics are responsible for drying the RMS out, I'm not a big fan of synthetic engine oils anyway. I'd only run a synthetic if I lived in an area that got uber-cold during the winter where synthetics do have a clear advantage. In nearly 60 years of running 99.99% conventional engine oils I've yet to have an engine problem. The only engine I ever only ran synthetics in was that BMW that sprang the RMS leak, I only ran synthetic in it since its warranty required it. It ran just as well with the conventional I changed it to to cure its RMS leak.

 

[machoheadgames]

Update. I replaced the rms many months ago, back in September. Ever since then, the tip of the transmission has been dry. However, it kept dripping from the skid plate for months. I thought maybe some oil was leaking out of my oil filter or that area, and then blowing back into the skid plate. I have been trying to track where this oil was coming from for so long.

The strange thing was that the oil dripping from the skid was clean engine oil, while (after many miles after rms change), the oil on my dip stick was black. But it kept coming and kept dripping consistently up until last week. Stopped dripping, its all dry, all my fluids are good. Haven't lost any engine oil. I guess this was clean oil from my few changes to high mileage oil in attempt to stop rms leak before changing. And it took months for it all of it to work its way out.

Glad my drip finally stopped, never thought it would take that long for oil throw upwards to work its way out.

Usually the skid plate leak is a cracked 4wd tailhousing on the back of the manual trans. It isn’t a visible crack until you pull the skid plate and remove the transmission mount and mount bracket.