• NAXJA is having its 18th annual March Membership Drive!!!
    Everyone who joins or renews during March will be entered into a drawing!
    More Information - Join/Renew
  • Welcome to the new NAXJA Forum! If your password does not work, please use "Forgot your password?" link on the log-in page. Please feel free to reach out to [email protected] if we can provide any assistance.

Identifying Oil pan gasket or RMS leak

Henrique - RS

NAXJA Forum User
Location
Brazil
Hello everyone,

Vehicle: Jeep Cherokee 98 4.0 with 5 speed (AX-15).

So I have recently replaced my RMS but it is still dripping oil.

This is what it drips after 15 min on idle:
https://photos.app.goo.gl/6nCUKrSLXaFR1Pc1A

And this is where the oil comes from, the front of the flywheel "inspection plate":
https://photos.app.goo.gl/eDkCHfga2kUNnyjv8

I need your help identifying if this is caused by the rear main seal, or the oil pan gasket. Since it's coming from the front of the inspection plate, transmission oil is discarded.

Please share your toughts. TYA!
 
I'm right there with you brother. I've had something like that leak forever. I had a remaned engine installed which presumably came with a new RMS and still seemed to have a weep there. With the change it seems to come and go, but there is a gasket or something visible above that spot that always seems moist. Let me know what you find.


98 AX-15 also.
 
Well, I don't see any dampness around your drain plug so I would lean "not the oil pan gasket. Did you use a new one when you did the RMS?

Check the back side (firewall) of your valve cover.

Did you have any issues removing the old seal? Did you apply the proper sealant on the rear cap and block side?

Are you sure you positioned the block side seal facing the correct way?
 
I'm just thinking out loud here ... but if the RMS was leaking, wouldn't the transmission
flexplate be wet with engine oil? Removing the inspection cover would confirm this.

Conversely; if the RMS was OK - and the oil pan gasket and/or valve cover gasket,
were leaking (only) - then the flexplate would be dry.

Just wondering. What do you all think?
 
Start at the TOP and work your way down, people always want to default to a RMS leak. Typical oil leaks on a 4.0 are Valve cover, distributor gasket (replace with an oring), and o-filter adapter o rings the the RMS and Oil pan. Sometimes you get leaks from the timing cover either the gasket or the crank seal and every once in a while you get a leak from the oil galley side (passenger side) of the head gasket.

Every single one of these leaks will rundown the motor and look like an RMS leak. The only way to know for sure is to clean up the engine really well and do some detective work or just start at the top and replace everything on the way down.
 
So I have searched around the engine and didn't find any leaks around the valve cover or oil filter area as cruiser54 suggests.

But what I did find was that the two 5/16" bolts that holds the oil pan in the RMS area were very loose. So I tightened them a little bit more. Of course now that the leak has developped it will only cease when I redo the oil pan gasket if that's the case but I'm hoping for at least some leak reduction with this, which will make me able to postpone the change (yeah, I do have a lot of other crap to fix in my shitbox, so that shouldn't be a priority right now).

I have cleaned the area below the oil pan/RMS area and the inspection plate really well, so I may follow up with the leak.

I don't drive the shitbox everyday, so I'll let you know what I do find later.
 
So I have searched around the engine and didn't find any leaks around the valve cover or oil filter area as cruiser54 suggests.

But what I did find was that the two 5/16" bolts that holds the oil pan in the RMS area were very loose. So I tightened them a little bit more. Of course now that the leak has developped it will only cease when I redo the oil pan gasket if that's the case but I'm hoping for at least some leak reduction with this, which will make me able to postpone the change (yeah, I do have a lot of other crap to fix in my shitbox, so that shouldn't be a priority right now).

I have cleaned the area below the oil pan/RMS area and the inspection plate really well, so I may follow up with the leak.

I don't drive the shitbox everyday, so I'll let you know what I do find later.

Did you put a socket on every valve cover bolt, including the 2 rearmost ones and see if they could be snugged up?
 
Did you put a socket on every valve cover bolt, including the 2 rearmost ones and see if they could be snugged up?

No I didn't, but what would be the point of that, once the valve cover is all dry and clean around? I have put my hand all over it and it is dry. The engine has no oil running around it, so it's definately either an oil pan or RMS issue.

I'll run it today and see if I find where it leaks now that the rear area of the oil pan/tranmission is all shiny and clean. I'll see if I can catch a leak on video.

Thanks!
 
So the leak continues....

https://photos.app.goo.gl/3ZZJ2JdKYMLsdWF59

Torqueing down the loose bolts didn't seem to make any difference. Guess I'll have to take it apart and change the damm gasket.
I won't redo RMS, that's for sure. I know I did it the right way, so the gasket will be my last attempt.

Good thing is that my oil will be always fresh new, since I'll have to keep pouring some from time to time heheheh.
 
Back
Top