Is it a Rear Main Seal Leak

[JLANEF]

I believe I have a RMS leak because there is a leak in that area. But I also worry it is not a RMS as I have power washed the bottom of the engine and tried to clean all the pan. When I drive for 10 or 15 miles now and pull back in the garage I have an “oil burning” smell for a good couple of hours. I have looked very carefully and there is no oil dripping on the exhaust pipes. The oil I find is dripping off the back of the oil pan, but mostly off the front/bottom of the tranny housing. My logic makes me think oil has to be running down the side of the block to be getting hot enough to smell. Oil at the bottom of the engine at the RMS shouldnt be hot enough to really stink should it? any advice on how to be sure it is the RMS?

 

[Fixer6]

Most likely a valve cover gasket leaking down the backside of the motor. Check there.

 

[LukesfirstJeep]

The oil I find is dripping off the back of the oil pan, but mostly off the front/bottom of the tranny housing.

That's where my RMS leak showed. If you have an automatic transmission, there an inspection cover. My RMS leak was running down the inside of that cover.

 

[JLANEF]

Thanks fixer and Luke. I am having a hard time seeing the top back of the motor fixer. I’ll work on getting a good inspection there. Luke, i am an auto, will that inspection cover come off without pulling the starter? Did you get a real burning oil stink with your leak? Seems like nothing down in there should be that hot.

 

[Modoc Guy]

If it’s the valve cover leaking, it might be running down the intake/exhaust side of the head a little. And if it hits the exhaust manifold, that could give that oil burning smell.

Actually if any oil dripping off the engine gets on any part of the exhaust pipe that would give you that burning smell.

You might want to get an inspection mirror and a flashlight and go looking for fresh oil all around the back of the engine.

 

[LukesfirstJeep]

Luke, i am an auto, will that inspection cover come off without pulling the starter? Did you get a real burning oil stink with your leak? Seems like nothing down in there should be that hot.

Yes, the inspection cover comes off without removing the starter. There are 3 bolts. I don't recall getting any burning or oil stick, but my leak was so small that I didn't need to add oil between changes. My leak did leave drops/puddles on the driveway.

Oil drops could be blowing off and hit the exhaust header and/or cat.

If you replace your RMS, look at the transmission cooler lines. If they need replaced, do it when you do the RMS because the exhaust header needs removed for both.

I also replaced my oil pan with the RMS. My OEM pan had a lot of surface rust. A new pan was a little over $40 and made in the US.

 

[cliffish]

It is much easier to replace the valve cover gasket first and see if it stops, both the valve cover and RMS are very common.

 

[cpwolf]

If you've cleaned it, and can't find the location, then do a dye test. Clean it, put some dye in there and hit a light in there. You should see it running on the back if it's the valve cover. I'd put dye in and run it idle in the garage and keep a light on it looking for the start.

 

[cpwolf]

Personally, I'd clean and do the dye test, and if it's the valve cover, I'd fix that, it's straight forward job. Then clean it and look and see. If you still have a leak and or drip, then I'd think RMS is the culprit. I wouldn't change that yet. I'd put in Mobil "Conventional" Oil High Mileage, not Synthetic. It has additives that can help the RMS. Before tearing that apart, I'd see if that helps. Maybe even a change or two if it doesn't drip much after that valve cover. That conventional switch fixed a RMS leak on my 2008 JK.