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Is it my rear main seal?

smcdonaldaz

smcdonaldaz

NAXJA Forum User
Location
Litchfield Park, AZ
I bought a '93 XJ in September with 119k miles. Not knowing the status of the fluids I decided to change them all a couple weeks ago. Prior to this I had a drop or two every couple days in the garage. Typical I understand. After changing the oil (didn't pay attention to the thickness of the old before dumping it @ checker) and driving it 20-25 miles I noticed A LOT, like a puddle (1-2 oz), of oil under the jeep. Drain plug was tight and the drops were coming from transmission side not the engine. It is definitely engine oil though. I put in Castrol high milage 20w50.

Thoughts before I do the RMS?
 
most likey rms, but when the valve cover leaks, it also leaks down the back of the head and engine and will show up in the same spot as the rms. check to make sure is not the valve cover first.
 
There are really two other oil leaks that can mimic a RMS.

1. Oif Filter Adapter leak - Check where the oil filter adapter mates to the engine block and make sure its not leaking from there. Also, make sure that the oil filter itself is tight in the adapter and not leaking. If the issue is your oil filter adapter, you will need to replace the o-rings within the adapter.
2. Valve Cover leak - This leak will usually run down the back of the engine block and make its way to the same area a leaky RMS would. I just take a paper towel and wipe the back of the cover to see if there is any fresh oil there. If this is your leak, you either need to snug down the valve cover bolts or you need to replace the valve cover gasket.

If its neither of these, then it's most likely your RMS.

Good luck
 
smokeman said:
There are really two other oil leaks that can mimic a RMS.

1. Oif Filter Adapter leak - Check where the oil filter adapter mates to the engine block and make sure its not leaking from there. Also, make sure that the oil filter itself is tight in the adapter and not leaking. If the issue is your oil filter adapter, you will need to replace the o-rings within the adapter.
2. Valve Cover leak - This leak will usually run down the back of the engine block and make its way to the same area a leaky RMS would. I just take a paper towel and wipe the back of the cover to see if there is any fresh oil there. If this is your leak, you either need to snug down the valve cover bolts or you need to replace the valve cover gasket.

If its neither of these, then it's most likely your RMS.

Good luck
Click to expand...
X2
 
smokeman said:
There are really two other oil leaks that can mimic a RMS.

1. Oif Filter Adapter leak - Check where the oil filter adapter mates to the engine block and make sure its not leaking from there. Also, make sure that the oil filter itself is tight in the adapter and not leaking. If the issue is your oil filter adapter, you will need to replace the o-rings within the adapter.
2. Valve Cover leak - This leak will usually run down the back of the engine block and make its way to the same area a leaky RMS would. I just take a paper towel and wipe the back of the cover to see if there is any fresh oil there. If this is your leak, you either need to snug down the valve cover bolts or you need to replace the valve cover gasket.

If its neither of these, then it's most likely your RMS.

Good luck
Click to expand...

Well, I already have the O-rings for the adapter because I know it has a slight leak. I just need to get the hex to get the danged thing off. I'll check the valve cover gasket for sure.

Thanks!
 
i have had multiple episodes of the oil pressure sender for the guage losing its internal oring and leaking out the side with the electrical connector. ussually this happens following an oil change due to it being placed right above the oil filter housing and when removing the filter it is very easy to tweak it. i would defintley check this are for wetness because it will leak down and look like a rear main for sure.
 
jkilcullen said:
i have had multiple episodes of the oil pressure sender for the guage losing its internal oring and leaking out the side with the electrical connector. ussually this happens following an oil change due to it being placed right above the oil filter housing and when removing the filter it is very easy to tweak it. i would defintley check this are for wetness because it will leak down and look like a rear main for sure.
Click to expand...

I had read about the fagility of the sender prior to the change and removed it. The reason I feel it's the RMS is that even after cleaning up the oil, it continued to leak, even after not driving it several days. Which of these other possibilities would do that?
 
In my case, I just replaced them all. I mean it's a 14 year old vehicle and the seals and gaskets are pretty cheap. I still need to replace my timing cover seal which is now leaking. :firedevil
 
smokeman said:
In my case, I just replaced them all. I mean it's a 14 year old vehicle and the seals and gaskets are pretty cheap. I still need to replace my timing cover seal which is now leaking. :firedevil
Click to expand...

An excellent point! I think I'll just do that then and be done with it.

Thanks everyone!
 
I had the leak at the rear of the engine and figured it was the rear main so I went ahead and changed it. Drove for a couple of days and the leak was still there. Decided to change the valve cover and oil filter adapter gaskets. Drove again and leak was still there. The oil was always dripping from the bell housing cover so I assumed it was the rear main seal still so i went to the local jeep dealership and bought an oem rear seal and installed it a second time. Drove again and it still leaked. This time I drove the Jeep until the engine warmed up and i crawled under it with a shop light and watched for the leak. It was coming from the oil filter adapter area. Once again I changed the seals on the adapter and still it leaked. Come to find out it was the gasket under the distributor had cracked and the oil was running sown past the oil filter adapter and being pushed back along the oil pan by the wind. The good news is I can change a rear main seal in record time.
 
desertrandy said:
.......................Come to find out it was the gasket under the distributor had cracked and the oil was running sown past the oil filter adapter and being pushed back along the oil pan by the wind. The good news is I can change a rear main seal in record time.
Click to expand...
I feel your pain, Bro. I was actually leak free for 3 months. Things have to be readdressed when warm weather returns. In the mean time I will not drive the XJ and park in my in-laws drive during the holidays to avoid the grief:yap:
 
This might narrow it down. I drained the oil Sunday and cleaned up the garage floor. I looked today and there is about half an ounce of oil under the Jeep. What could still be leaking?
 
i was told that the rear main will only leak while running so if you park it and turn it off it should not leak, but then if you let it sit at idle it will..... what about the oil pan gasket at the rear of the engine?
 
mitsumotors said:
i was told that the rear main will only leak while running so if you park it and turn it off it should not leak, but then if you let it sit at idle it will..... what about the oil pan gasket at the rear of the engine?
Click to expand...

That's wishful thinking. LOL. All of my Jeeps leak/have leaked/will leak at the RMS and they all mark their territory overnight.

If you used the multi piece cork gasket, you may have messed up the rear gasket a bit. The last one I did, I got the single piece reinforced rubber gasket from NAPA. Installed much easier. No leaks (for awhile).
 
yeah, i did my rear main two weeks ago and my oil pan gasket, which was a multi piece. now it is leaking alot and it looks like the rear main but i'm hoping its the oilpan gasket.
 
kevin s said:
That's wishful thinking. LOL. All of my Jeeps leak/have leaked/will leak at the RMS and they all mark their territory overnight.

If you used the multi piece cork gasket, you may have messed up the rear gasket a bit. The last one I did, I got the single piece reinforced rubber gasket from NAPA. Installed much easier. No leaks (for awhile).
Click to expand...

Haven't done oil pan yet but will be doing that with the RMS and oil filter adapter this Sunday. I'll pick up a valve cover gasket and do that too if time permits. I felt the back of the engine below the valve cover and it didn't have anything fresh so I'm confident it's not the valve cover gasket.
 
I thought I would piggyback on this post since there is a lot of action. I also am in the midst of doing the RMS. I'm getting ready to continue this morning since I couldn't get the oil pan out past the axle. I have 3" of lift (with discos) and jacked the frame up with a hi-lift until the front tires were off of the ground. The pan is hanging up on the steering stabilizer and axle. My question is will the steering stab removal allow it to drop out or should I just unbolt the shocks. If there isn't any response I'll just go check it out but was wondering if anyone had a quick answer for it. First RMS in 200,000 miles...I guess I am just lucky so far!
 
XJ AV8R said:
I thought I would piggyback on this post since there is a lot of action. I also am in the midst of doing the RMS. I'm getting ready to continue this morning since I couldn't get the oil pan out past the axle. I have 3" of lift (with discos) and jacked the frame up with a hi-lift until the front tires were off of the ground. The pan is hanging up on the steering stabilizer and axle. My question is will the steering stab removal allow it to drop out or should I just unbolt the shocks. If there isn't any response I'll just go check it out but was wondering if anyone had a quick answer for it. First RMS in 200,000 miles...I guess I am just lucky so far!
Click to expand...
when i did my oil pan i just put a jack at the back of the engine and a block of wood up to the lip on the rear of the engine, then i jacked up and the change in the angle of the engine allows the oil pan to drop right out. it was real easy. also, when i changed my rms i had 450,000km's and it was the first time doing it.... beat that:cheers:
 
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