Best method for sealing oil pan?

[HammeredSole]

After completing an extensive restoration of my 2004 Wrangler 4.0, I've had great success with getting everything back together. Every single gasket, seal, or component needed service after 20 years at 67,000 miles. I got a clean seal from the front main, cam gear cover, water pump, thermostat housing, etc. Valve cover went back on and is dry as a bone with the proper cleaning and the FelPro gasket. I completed the RMS with a FelPro RMS and FelPro oil pan gasket, and that's the only outstanding problem I have. I meticulously prepped and installed the RMS, but the pan gasket seems to be an issue.

I get a consistent dribble down the front center of the transmission plate. I've taken the starter and dust plate off to check out the inside of the plate, flex plate, bell housing, etc, and everything inside is dry. I used Toyota FIPG and cleaned everything very well, but while putting the pan back on, it's immediately apparent that the circular shape of the gasket is unsupported during install, and if it folds over it's basically impossible to tell. I've attempted loosening and retorqueing to spec, etc.

So, I've scoured the forums and found lots of discussion on the topic, but I'd like to get all the best advice I can before I tackle this again. I've got a brand new OEM oil pan, FelPro gasket, and Ultra Black RTV this time. What techniques do you find best to secure the oil pan gasket while installing? I've contemplated using 3M spray adhesive to actually hold the gasket in physical contact with the block, because I feel the issue is a slight kink or fold in the gasket that I just can't see in the rounded area of the rear main cap.

 

[Sensei]

 

[GregBelleville]

After completing an extensive restoration of my 2004 Wrangler 4.0, I've had great success with getting everything back together. Every single gasket, seal, or component needed service after 20 years at 67,000 miles. I got a clean seal from the front main, cam gear cover, water pump, thermostat housing, etc. Valve cover went back on and is dry as a bone with the proper cleaning and the FelPro gasket. I completed the RMS with a FelPro RMS and FelPro oil pan gasket, and that's the only outstanding problem I have. I meticulously prepped and installed the RMS, but the pan gasket seems to be an issue.

I get a consistent dribble down the front center of the transmission plate. I've taken the starter and dust plate off to check out the inside of the plate, flex plate, bell housing, etc, and everything inside is dry. I used Toyota FIPG and cleaned everything very well, but while putting the pan back on, it's immediately apparent that the circular shape of the gasket is unsupported during install, and if it folds over it's basically impossible to tell. I've attempted loosening and retorqueing to spec, etc.

So, I've scoured the forums and found lots of discussion on the topic, but I'd like to get all the best advice I can before I tackle this again. I've got a brand new OEM oil pan, FelPro gasket, and Ultra Black RTV this time. What techniques do you find best to secure the oil pan gasket while installing? I've contemplated using 3M spray adhesive to actually hold the gasket in physical contact with the block, because I feel the issue is a slight kink or fold in the gasket that I just can't see in the rounded area of the rear main cap.

Did you dab rtv on the corners front and rear? As far as holding the gasket on, my fel pro came with plastic dowels that screwed into the oil pan holes to hold the gasket on and guide the pan into place.

 

[macleanflood]

The last time I did my oil pan was in the gravel parking lot of a Napa after smashing in the pan. I installed it without any RTV and zero issues.

Wondering if it's your rear main or even your valve cover gasket. Super easy to pinch something with the valve cover and not get it down.

-Mac

 

[HammeredSole]

The last time I did my oil pan was in the gravel parking lot of a Napa after smashing in the pan. I installed it without any RTV and zero issues.

Wondering if it's your rear main or even your valve cover gasket. Super easy to pinch something with the valve cover and not get it down.

-Mac

Yep. 100% not the valve cover. I guess I'll find out when the pan comes off. I really hope it's not the rear main, as it's such a tedious thing and I was so incredibly meticulous with the RMS install. I'm feeling like it's the oil pan gasket in the curved groove of the rear main cap. The leak seems more profuse when I drive it up a steep incline. One thing is for certain, this is annoying.

 

[Rickyd]

Many people using the felpro rear main seal get leaks. Including me on a new stroker motor. The Mopar seal is supposed to be the go to. No issues with a fel pro oil pan gasket on an old pan with a bunch of dents

 

[MikeE024]

The last time I did my oil pan was in the gravel parking lot of a Napa after smashing in the pan. I installed it without any RTV and zero issues.

Wondering if it's your rear main or even your valve cover gasket. Super easy to pinch something with the valve cover and not get it down.

-Mac

You got away with a method you performed in a pinch. But, it’s better to recommend following the FSM so we don’t set folks up for failure.

 

[sab]

For me, inadvertently skipping the RTV definitely caused a leak, as I noted in this post:

Post in thread 'Putting oil pan back on, does the back fit weird? 2006 TJ'

Jul 31, 2024

When I did my valve cover, RMS, and oil pan gasket back in May 2023, I got very discouraged because when I was done, it leaked profusely, and when I started it was a very minor leak. I was afraid I'd have to re-do the RMS again. As I started to re-play in my mind what I did, I realized that I did not put RTV in the corners where the oil pan gasket goes from flat to semi-circular at the rear crank journal/RMS. I knew about the importance of that RTV, but in my disheveled way of doing projects, I "saw a squirrel" while putting the RTV on it, and had missed it at the rear. So I ended up...

• sab

 

[macleanflood]

You got away with a method you performed in a pinch. But, it’s better to recommend following the FSM so we don’t set folks up for failure.

Agreed.

-Mac

 

[Irun]

I've installed numerous RMS, using FelPro, and generally had good results. However, recently I went through two, in the same vehicle, that wouldn't stop leaking. On the third round I switched to a Mopar seal and it has worked thus far.

As you already know, cleaning everything and following the FSM instructions is key to success. In terms of the RTV, I use Ultra Black, but only use that sparingly on the front part of the pan where the timing cover gasket and oil pan gasket come together on the corners. The back part of the pan also gets a couple dabs of Ultra Black on the outside corners of the pan. The RMS itself gets a thin coat of Anaerobic gasket maker, applied on the corners where the two halves come together. The factory calls for Mopar, but I've used Permatex with good success.

 

[HammeredSole]

The seal gets anaerobic sealer? That stuff hardens and has to be chipped or scraped off. How's that going to work in the upper channel, and it it gets on the flange part of the seal?? I think I need a deep dive redo, and I'm wondering if the FelPro RMS is the culprit, it seemed to be a little too long on the top and had excess exposed on both ends when centered.

 

[sab]

It's needed to keep oil from seeping through the gap in the two halves of the rear crank bearing block:

 

[HammeredSole]

It's needed to keep oil from seeping through the gap in the two halves of the rear crank bearing block:

View attachment 576673

Oh, yea well that got the sealant, but that's a lot different than the "seal itself"

 

[sab]

Oh, yea well that got the sealant, but that's a lot different than the "seal itself"

Yes, it is. I missed that part. @Irun, you really put the anaerobic sealant on the seal? I wouldn't recommend that. That seal, which is stationary, contacts the crank journal, which is rotating. Anaerobic sealant, like RTV, is not meant to be used in a sliding interface.

 

[Irun]

Yes, it is. I missed that part. @Irun, you really put the anaerobic sealant on the seal? I wouldn't recommend that. That seal, which is stationary, contacts the crank journal, which is rotating. Anaerobic sealant, like RTV, is not meant to be used in a sliding interface.

Only on the mating surfaces, where the two halves join. Edited the post to make that clear!