At wits end with rear main seal

[hank826]

2004 Jeep Wrangler sport 4.0 I know this topic has been visited more times than any of us can count but over about the last two weeks I have replaced my rear main seal two times, originally it was leaking maybe 10 to 15 drops after I shut it off and parked it leaving a pretty unsightly oil spot in myself and others driveways. I have followed and studied and performed almost every forum suggestion on this forum and all other jeep forms, I have watched YouTube videos used the factory service bulletins alas, it still leaks about one to two drops per second while running.

There is no groove in the crank, either visually or by fingernail test, I cleaned the seal passages in both the block and the bearing cap. I applied anaerobic sealant where indicated in the factory service bulletin, I have cleaned the bearing cap bolts to ensure proper torque, The second time around, I bought the $90 OEM Mopar rear main seal. All bolts got properly torqued. While installing the rear main seal I used the plastic shoehorn that came with the Felpro kit on both the felpro and the mopar seal, cleaned both bearing cap sealing surfaces probably cleaner than they were assembled at the factory. I haven’t tried yet to offset the rear main seal as some have recommended in the forums, this wasn’t the original design of the seal and multiple people have said it’s too likely to mess up the RMS while installing.

Otherwise, I added our RTV Everywhere it has been recommended (corners of the rear bearing cap after it’s installed, corners of the timing cover) I let the anaerobic sealant dry/cure for about 36 hours the RTV for about 24 hours. Prior to applying RTV and the anaerobic sealant the engine oil was drained for about 36 hours.

I’m losing my mind here with this folks. What do I do?

 

[TheBoogieman]

Pay a professional that warranties their work or live with your sub-par work. My RMS leak was a valve cover gasket leak.

 

[OldBuzzard]

It sounds like you're doing everything right.

Are you sure it's not coming from the valve cover?
Are you sure it's not coming from the oil pan gasket?
Are you sure it's oil, not ATF or tranny lube?
(just questions we have to ask)

 

[hank826]

Verified not coming from the valve cover. Oil pan gasket should be good as it’s been brand new both times and it’s leaking down the tranny inspection cover. Prior to doing the work RMS it wasn’t even leaking as bad as it has since I changed it. And it’s engine oil. Same color (and smell) as what I poured in 5 minutes before.

 

[JEEPSTEVENANAIMO]

get some leak oil dye from your parts store. see where its really coming from. figure it out before you throw more money at it.

 

[hank826]

get some leak oil dye from your parts store. see where its really coming from. figure it out before you throw more money at it.

I’m not sure what that would do at this point. I can visually see that it’s not coming from the valve covers. And the only other two options are the back of the oil pan gasket, and the rear main seal. Obviously I can’t differentiate between the two because their proximity to each other. But I’m almost certain it’s the RMS

 

[hank826]

I’m not sure what that would do at this point. I can visually see that it’s not coming from the valve covers. And the only other two options are the back of the oil pan gasket, and the rear main seal. Obviously I can’t differentiate between the two because their proximity to each other. But I’m almost certain it’s the RMS

I said covers I meant cover.

 

[JEEPSTEVENANAIMO]

I’m not sure what that would do at this point. I can visually see that it’s not coming from the valve covers. And the only other two options are the back of the oil pan gasket, and the rear main seal. Obviously I can’t differentiate between the two because their proximity to each other. But I’m almost certain it’s the RMS

So you just explained why you need the dye. not gonna lie....you should leave this to someone who actually knows what they are doing because you clearly do not.

 

[OldBuzzard]

So you just explained why you need the dye. not gonna lie....you should leave this to someone who actually knows what they are doing because you clearly do not.

I think he knows what he's doing, it's just a difficult job which lots of smart people struggle with. He's right — dye won't help if the only place it can be coming from is the RMS or the gasket right next to the RMS, both hidden between the oil pan and the tranny.

Sorry, Hank, but I can't really help. Hopefully some of the guys who have struggled with this and finally got it right will chime in and provide hints.

 

[lBasket]

LS swap it

 

[hank826]

So you just explained why you need the dye. not gonna lie....you should leave this to someone who actually knows what they are doing because you clearly do not.

I think we may have gotten off on the wrong foot sir and I believe I’m lashing out due to frustration over my issue so I’m sorry, I was being rude.

Let me start over, I’m fairly knowledgeable with the 4.0. this specific engine I rebuilt about 60K miles ago due to a cracked piston skirt, it was holding great for the first 50k miles but got progressively worse for the better part of a year. I’ve cleaned the rear of the engine as best as I could over the last few weeks to try and be able to pin point exactly where my leak is happening.

While running I can use an inspection mirror and verify the back of the head is dry and does not have oil running down it.

From what I can understand and see, an oil pan leak from the rear (near the RMS) and a rear main seal look almost indistinguishable from each other. That’s what I meant by not seeing the purpose of the dye, I haven’t used it before and have no experience with it so I’d love to hear how it works and your experience with it. Again I’m sorry I was being an a-hole I’m just getting tired of laying under the thing

 

[hank826]

LS swap it

I’m starting to think that a small black Chevy with a CFI set up and a turbo 400 might be better for my psyche then to lay underneath this thing and do another rear main seal

 

[lBasket]

I’m starting to think that a small black Chevy with a CFI set up and a turbo 400 might be better for my psyche then to lay underneath this thing and do another rear main seal

LS is a SBC!!!!

 

[Grenadiers]

The edge of the block is pretty sharp. You didn’t skim off any of the seal on install? Also the rigid block seal portion needs to follow the path exactly, if you bent it slightly, you’ll get a leak.

 

[Chris]

Find a shop that specializes in Jeeps and has done this job before. One that will warranty their work.

 

[hank826]

LS is a SBC!!!!

True true, but I was thinking the older Chevy engine, I think maybe gen 3 and on was the LS? Maybe I’m wrong I don’t have too much experience with them.

The edge of the block is pretty sharp. You didn’t skim off any of the seal on install? Also the rigid block seal portion needs to follow the path exactly, if you bent it slightly, you’ll get a leak.

Yeah I noticed the sharpness as well, hence why I used the little plastic thing that comes with the felpro RMS for both installs. I’m fairly certain as well that I didn’t damage the seal putting it in when I remove the old seal I used very small cotton gun patches with a little bit of brake clean applied and pushed them through the block around the crank with the old seal to clean up the inside. By the time I got around to putting in the new seal, it slid in with just my fingers, for the very end of it, maybe the last 1/4” I had to drive it in very lightly with a wooden chopstick I had laying around in my kitchen.

 

[hank826]

Find a shop that specializes in Jeeps and has done this job before. One that will warranty their work.

That’s my next idea option for sure, I’m usually anti-shop because i take a lot of pride in tough challenges and learning the ins and outs of things and it makes me a lot happier driving it around knowing I’ve done everything myself. And obviously the cost, but at this point I’m declaring war with this rear main seal so a shop might be an answer.

 

[lBasket]

That’s my next idea option for sure, I’m usually anti-shop because i take a lot of pride in tough challenges and learning the ins and outs of things and it makes me a lot happier driving it around knowing I’ve done everything myself. And obviously the cost, but at this point I’m declaring war with this rear main seal so a shop might be an answer.

If you put an engine skid on it you won't be able to tell if it's leaking

 

[Chris]

That’s my next idea option for sure, I’m usually anti-shop because i take a lot of pride in tough challenges and learning the ins and outs of things and it makes me a lot happier driving it around knowing I’ve done everything myself. And obviously the cost, but at this point I’m declaring war with this rear main seal so a shop might be an answer.

The rear main seal on the 4.0 is an awful design to begin with. Getting it to not leak any oil whatsoever is something that only comes with a lot of experience I feel like.

You complaint is one we hear very, very often. @ReconMarine who is local to me is dealing with the same issue.

 

[hank826]

The rear main seal on the 4.0 is an awful design to begin with. Getting it to not leak any oil whatsoever is something that only comes with a lot of experience I feel like.

You complaint is one we hear very, very often. @ReconMarine who is local to me is dealing with the same issue.

Yeah I have no complaints with leaks. But if I idle the engine over concrete for 10 minutes there is about a 9”x9” puddle under. It’s excessive