Zillionith Rear main seal question I'm sure.

[cityjack]

Good evening all,

After weeks and literally a hundred or so dollars on gaskets doing the same old thing slightly different over and over and countless hours of scouring the various forums I am stumped. I am going to apologize before hand for the hopefully not too long of a story I am about to give you all. I just want to give you gusy all the pieces so HOPEFULLY someone can shed some light on what I am possibly missing or doing wrong.
The patient is my 82 CJ5 , AMC 258 i6 / 4.2l with a 4-spd. Probably over a 150K on the motor.

Last summer the oil leaks from the valve cover and what I thought was the rear main seal got so bad they began to saturate the clutch and pressure plate to the point where the jeep would shake so bad when I let the clutch out it would almost shake me out of the vehicle. I like a dumb a** ignored it until I broke the throwout bearing in half and could not shift into reverse or first without first turning the jeep off then restart once in gear.
removed the tranny. Totally cleaned the whole underside of the vehicle and all of the tranny and Transfer Case . Put a new aluminum valve cover on. A new clutch, pressure plate and throw out bearing. 1st time - New rear main seal and oil pan gasket. Put RTV(Blue gue) on the corners of oil pan gasket where it meets the rear main cap, under and on top of the rear main seal sides the half that goes in the cap and also where the two seal meet. Assembled back together. At idle no leak. Sitting in neutral at higher than idle rpm no leak. Drive down the road for about five minutes and back to the drive way. Oil is raining down from between the inspection plate and the tranny bellhousing. 2nd time - Took it all apart, thought maybe we inadvertently put a little tear in the seal that goes into the block. Re RTV'ed(Blue gue) the exact same way except this time I put RTV under the seal that fits into the rear main cap. Put it all back together. Exact same results at the exact same time. No leaks when sitting still. Only when it goes for a ride. 3rd time - took it apart. At closer inspection it appeared as if oil was escaping under the oil pan gasket between the gasket and the oil pan where it sits on top of the rear main cap. We put a new oil pan gasket on with only this time we used Permatex Gray RTV and this would have been the second Felpro 1 piece gasket with metal in it. Same results at excatly the same time. No leaks when sitting still at idle or above. Only after a drive. 5 minutes usually will produce oil. Still leaks pretty good. A bunch of oil drops hanging from the gap in the inspection plate and the tranny bellhousing. After reading on a forum somewhere that there should be absolutely no RTV on the backside of the seal where it sits into the rear main cap. I planned to tear it down AGAIN the coming weekend. But before the weekend I thought I'd give the 9 dollar Bars Leak rear main seal fix a try. I normally don't ever use "fix it in a bottle", but I figured what the heck, I was going to tear it down again anyway. Wasted 9 dollars. 4th time - Tore it down and when I removed the oil pan the rear of the oil pan gasket sprung out of its area where it sits in the oil pan on top of the rear main cap. The oil pan gasket grew ALOT and I didn't know why. That was until my friend explained what that BARS Leak does. Swells gaskets. At closer look it appeared that my oil pan was bent in the rear of the pan where it mates up to the rear main cap. Evidently from when I let the pan hang down one time with the two rear pan bolts still in. This made for excess room for the oil pan gasket to grow and obviously not seal. I thought I FINALLY found the smoking gun. My friend who is an exactly metal fab guy helped me tweak the pan back into shape however so slightly. Same pan gasket and back together it went. I left the rear main seal alone. Same results, same way. No leaks when sitting still only after a 5 minute drive. I thought ok. Its gotta be that RTV that I put on the back side of the rear main seal thats up in the cap. 5th time - tore it apart removed the seal out of the cap. Cleaned the rear main cap with brake cleaner very well. Removed all RTV and put a new seal with gray RTV on the chamfered edges of the cap the cap surface adjacent to the sides of the seal that is in the cap but NOT at the points where the two seal halves meet. The seal directions that came in the box said to NOT do that although I did it every other time before this. Put a new oil pan gasket in, tossed the swelled one and got rid of the oil that had the seal fixer in it as well. Put RTV at the corners on the oil pan gasket where I'm supposed to. Torqued oil pan to spec. Assembled like always to the "T". SAME FRICKIN RESULTS. Should I have put a little dab on the 2 points where the two seal meet? I have nothing that I can feel on the crank surface where the seal rides as far as a groove goes. I do however have a score mark on the rear main bearing from a small burr somewhere on the crank, but th complete rest of the bearing has its gray material still intact telling me the bearings were replaced sometime in the not too distant future. The motor has got to be tired though because at idle I have little to no oil pressure. I'm assuming the previous owner must have just put bearings in and didn't touch the cylinder walls or put rings in. My PCV valve is fine. No leaks from a oil pressure sending unit or base distributer. I can see its coming from between the inspection cover and tranny.
I've read two things I have not looked into or thought of;
1. Worn thrust bearing allowing the rear main seal to move from crank movement.
2. Blow by I've read maybe.

Any help would so much appreciated. I am so so tired of crawling under this thing. 3 rear main seals. 3 oil pan gaskets. 2 oil changes and countless man hours. I'm getting tired but I do not want to give up. I will not let this oil leak kick my a**

HELP ME PLEASE!

Sid

 

[CJ]

:ww: cityjack!

You sure have been through a lot! My first and strongest thought is that the crank journal where the seal rides is slightly worn. If you have good oil pressure it takes only a slight indentation for the seal to leak.

Did you notice anything?

 

[cityjack]

Hey CJ,

Thanks for the quick reply. When I run a finger nail over the crank journal where the seals rides I cannot feel a groove or anything like that. I run 10w-40 always. I have close to zero for oil pressure at idle which is somewhere between 800 and a 1000 rpm's. Engine when warm tends to make some noise at that point but nothing excessive. The motor still has some get up and go but I'm sure it could have more for its age. Do you think me not putting a dab of RTV on the seal ends where the two halves meet could be the problem this time? I've seen where some say to offset the two seal halves but that is not possible with the seal half that is in the bearing cap due to its outer flange ends. If the crank journal IS worn I've also seen where some talk about a sleeve to go over the worn part of the crank much like a sleeve that goes over a crank harmonic balancer for a front seal. I never heard of a sleeve for this part of the crank though. What do you think about possible crank case pressure caused by blow-by due to ring wear? I do have a working PCV valve, or at least I can blow thru it one way and not the other. I'll need to check the routing of it though because the top end of this motor is surely "jury rigged" to say the least from the previous owner.
Thanks for your help.

Sid

 

[IOPort51]

150K is not a lot of miles for a AMC 258 i6 / 4.2l .
only two sources of oil in this location, can we rule out the Transmission front seal??
I gotta go with CJ on this one.
I once read of checking seal areas with magic marker and a single edge razor blade. Clean the surface and paint it with the marker. drag or slide the razor to remove any on the high spots. the trick is keeping the blade square with the journal. And of course don't scratch anything.

 

[Rescue Diver]

One big question. How well vented is your valve cover????? Do you have a breather cap, and if so, can you blow air through it easily? With the miles you have on your AMC 258 i6 / 4.2l , it has to be making a fair amount of blow by. If your breather and PCV are not allowing this blow by to escape then you'll get a whole lot of pressure in your crank case, and IT WILL cause oil to be forced through otherwise good seals. Trust me on this. I know from personal experience. After installing my new 4.0 head, valve cover, breather, and PCV valve, it suddenly had a front seal leak. I went to all the trouble of replacing the timing cover seal for nothing because as it turns out, it was caused by my brand new Mr. Gasket oil breather being too restrictive to allow the modest amount of blow by that my engine makes from escaping. After changing the seal and installing a micro sleeve on the harmonic balancer, I was pissed to find it still leaking! I compared the new oil breather with the old one from my previous valve cover which was only a few months old, and the old one was easy to blow through, while the new one you would get red in the face trying to blow through. I switched back to the old one and went to the car wash to clean off the oil from all over under the jeep and after putting some miles on it, the pan is still dry!!!

Little things like that will drive you nuts!

What valve cover do you have? Does it have baffles? My 4.0 valve cover had seriously restrictive plates in the baffles. I removed them to help it breath even more. Make sure there are no restrictions that will keep the blow by from reaching your oil breather and PCV, and make sure they both flow easily. If you cant easily exhale through your breather, neither can your engine. Try it and you might be surprised to find the leak goes away. Of course if that does fix it, you'll feel really stupid for putting so much work into replacing that seal repeatedly, but that's what owning a Jeep is all about!

 

[cityjack]

Hey all,
I really never thought about the front of my tranny leaking. I do not remember it being wet in there when I originally did the clutch job. As far as a blow by problem...I have a brand new Aluminum cast valve cover. I have the PCV valve in the front PCV hole and the rear PCV hole has just got a breather tube stuffed in that goes straight to the air cleaner. The filler cap is just a tight A** rubber plug. Yes there are definitely some baffles up under the new valve cover too. Are you guys saying I should have a breather cap for a filler cap instead of that provided rubber plug? Like I was saying I think, the top of the motor, wires and vacuum lines routing leave something to be desired. Where should I run the PCV valve to? I have a Haynes and I'll check that as well. I am going to try all this blow-by remedy stuff before I go back in again to check crank journal options. Just for questions sake, do they make a rear main seal journal sleeve? I never heard of that. If they do, how would you install it? I know on the other end you just slide it on and then the harmonic balancer.
Heading to the driveway now and I'll update you guys shortly. Another thing real quick, any sure way WITHOUT removing the tranny to know if its engine oil or gear case oil?

Thanks

Sid

 

[Rescue Diver]

Hey all,
I really never thought about the front of my tranny leaking. I do not remember it being wet in there when I originally did the clutch job. As far as a blow by problem...I have a brand new Aluminum cast valve cover. I have the PCV valve in the front PCV hole and the rear PCV hole has just got a breather tube stuffed in that goes straight to the air cleaner. The filler cap is just a tight A** rubber plug. Yes there are definitely some baffles up under the new valve cover too. Are you guys saying I should have a breather cap for a filler cap instead of that provided rubber plug? Like I was saying I think, the top of the motor, wires and vacuum lines routing leave something to be desired. Where should I run the PCV valve to? I have a Haynes and I'll check that as well. I am going to try all this blow-by remedy stuff before I go back in again to check crank journal options. Just for questions sake, do they make a rear main seal journal sleeve? I never heard of that. If they do, how would you install it? I know on the other end you just slide it on and then the harmonic balancer.
Heading to the driveway now and I'll update you guys shortly. Another thing real quick, any sure way WITHOUT removing the tranny to know if its engine oil or gear case oil?

Thanks

Sid

If it's gear case oil, it would start leaking less as the level gets below the input shaft. If the gasket that seals the whole seal assembly is leaking, it would continue until you're really low on gear oil.

So your rear valve cover hole just has a hollow tube that goes to the air cleaner? That should work fine. Make sure everything is opened up. What kind of cast aluminum valve cover do you have, and aftermarket one? If so, I'd think the baffle in it would breath just fine.

Your PCV valve should run to an unported big vaccum line directly to the intake, or to a large port on the base of your carb. If you can install an oil breather cap in place of your oil cap, that would help a lot too. Crank case pressure will make good seals leak, and cause what would otherwise be a small drip to be a big leak because the oil is being forced out under pressure while you drive.

I've never heard of adding a micro sleeve to the rear of a crank. I don't think they make them because I can't imagine how you would install it? Maybe I'm wrong. Hopefully someone chimes in if I am.

With your miles, I seriously doubt the crank would be worn enough to cause your leak anyway.

I've never had a crank cause a rear seal leak. As long as you put the seal on with the lip facing inward, I'd think that would be good enough.

 

[cityjack]

Hey Diver,

It is an aftermarket cast aluminum valve cover. The PCV valve goes directly to a large port on the base of the carb. My filler cap is a plug though. Maybe somehow I can come up with something to close the hole but at the same time let it breathe through there. Do you know of an aftermarket breathercap that will fit that "push in hole"? What do you think about possibly worn bearings letting the crank move back and forth? Maybe a worn thrust bearing? I'm not to confident with that because like I said earlier, the rear main bearing has completely ALL of its gray material still there and just a minor hairline scratch is all. I'm going to go out in the rain and look to see if the rear valve cover hole is clogged to the air cleaner. I don't think so though.

Sid

 

[Rescue Diver]

Hey Diver,

It is an aftermarket cast aluminum valve cover. The PCV valve goes directly to a large port on the base of the carb. My filler cap is a plug though. Maybe somehow I can come up with something to close the hole but at the same time let it breathe through there. Do you know of an aftermarket breathercap that will fit that "push in hole"? What do you think about possibly worn bearings letting the crank move back and forth? Maybe a worn thrust bearing? I'm not to confident with that because like I said earlier, the rear main bearing has completely ALL of its gray material still there and just a minor hairline scratch is all. I'm going to go out in the rain and look to see if the rear valve cover hole is clogged to the air cleaner. I don't think so though.

Sid

With your engine having, what did you say, 158k on it, or somewhere around that, and the bearing being in good shape, I seriously doubt it's your crank.

If you're wanting a breather in place of your push in cap, maybe you could just buy a regular breather and find a grommet in the help section of O'Reillys to make it fit the hole? I've heard people talk about actual "Breather Caps" but I don't really know anything about them.

 

[IOPort51]

I have a 97 valve cover on a 4.0 on a AMC 258 i6 / 4.2l . I think the restriction plates in the valve cover is/are the PCV valve. I have been loosing a bit, lets say Way too much, oil from the rear main I think I shall check this option ASAP. gonna have to do something, some of the clowns at work are calling it the Exxon Valdez.
gonna see what a can of carb cleaner will do for it.

 

[Rescue Diver]

I have a 97 valve cover on a 4.0 on a AMC 258 i6 / 4.2l . I think the restriction plates in the valve cover is/are the PCV valve. I have been loosing a bit, lets say Way too much, oil from the rear main I think I shall check this option ASAP. gonna have to do something, some of the clowns at work are calling it the Exxon Valdez.
gonna see what a can of carb cleaner will do for it.

Is the 97 valve cover the aluminum one with the ridges on top like the 95?

If so, unbolt the baffles from underneath and remove the metal plates, then re-install the baffles. Their only screwed on with three bolts each that take a 1/4" socket, and the plates are sandwiched between the baffles and the valve cover with a pair of gaskets. Without the plates you'll still have baffles that open up near the surface of the head to keep oil from being sucked up in the PCV or breather tube. I figure without the plates, it's set up exactly the way the AMC 258 i6 / 4.2l was originally meant to be.

Mine was really dumping quite a bit of oil from the front seal all over the underside of my engine and on my front axle before I removed those damn plates and opened up my oil breather by bending the metal restrictor open and ripping out a little of the foam rubber with needle nose plyers. It still has foam between the valve cover opening and the breather tube that goes to the air cleaner, but I made it thinner so it would breath a little.

Two days of driving to work on the far end of Kansas City and my oil pan is still clean after those changes!

 

[IOPort51]

what are you using for a PCV valve??

Is the 97 valve cover the aluminum one with the ridges on top like the 95?

If so, unbolt the baffles from underneath and remove the metal plates, then re-install the baffles. Their only screwed on with three bolts each that take a 1/4" socket, and the plates are sandwiched between the baffles and the valve cover with a pair of gaskets. Without the plates you'll still have baffles that open up near the surface of the head to keep oil from being sucked up in the PCV or breather tube. I figure without the plates, it's set up exactly the way the AMC 258 i6 / 4.2l was originally meant to be.

Mine was really dumping quite a bit of oil from the front seal all over the underside of my engine and on my front axle before I removed those damn plates and opened up my oil breather by bending the metal restrictor open and ripping out a little of the foam rubber with needle nose plyers. It still has foam between the valve cover opening and the breather tube that goes to the air cleaner, but I made it thinner so it would breath a little.

Two days of driving to work on the far end of Kansas City and my oil pan is still clean after those changes!

 

[Rescue Diver]

what are you using for a PCV valve??

1974 Monte Carlo. It allows a few inches drop in vaccum compared to the PCV valve that my AMC 258 i6 / 4.2l originally calls for, but it scavenges the crank case pressure better and it fits a grommet I found in the help section at O'Reilly's.

 

[cityjack]

Hey guys,

After a weekend of looking at my AMC 258 i6 / 4.2l with my buddy we are definitely thinking the blow-by could quite possibly be the culprit. It was raining here all weekend and I just couldn't put any descent time in on it. As I told you all the top of my engine is a bowl of spaghetti from the previous owner with all the vacuum hoses and wires go everywhere and nowhere. I definitely have a substantial vacuum leak somewhere and my motor will not even idle and stalls at all stops. My friend said that if I have that bad of a vacuum leak then the PCV valve is being robbed of vacuum and not doing ITS job exhausting the crankcase pressures. I am going to get rid of every single emissions piece of and plug the two vacuum solenoid holes in the intake manifold. The Haynes manual is really not much help in vacuum line routing. I will keep the ABSOLUTE mandatory vacuum lines only. If I have to, I'll take the aluminum after market valve cover off and remove the plates under the baffles as well. This blow-by has got to be the problem. I have to snag a couple of 5/8" pipe plugs for the manifold tomorrow and I'll let you guys know what the story is.

Thanks all very much for your input and help.

Have a nice night.

Sid

 

[cityjack]

Alrighty then,
Finally got some sun over my way and did a bunch of work on the vacuum lines of my AMC 258 i6 / 4.2l TRYING to remedy this oil leak. I removed every single inch of emissions related vacuum line and only kept the absolute bare necessity vacuum hookups. I removed both vacuum solenoids that go into the intake manifold and plugged them both. That removed about 3 lbs worth of junk. I have the PCV valve that is in the front of the valve cover going to a T right above it. Actually I think the T is part of the PCV. Anyway, the larger side goes directly to the large vacuum port at the base of the carb. The other smaller side of the T is plugged. EGR is plugged. All unnecessary carb ports are plugged. I have the vacuum for the distributor still going to the carb. I think thats the ONLY line other than the PCV going to the carb now. The engine idles way smoother now. I definitely had some vacuum leaks. The carb still needs adjusting, but thats another story for another day.
After I made sure there was no oil on the bottom of the inspection plate where it usually shows up, I started it up. Let it warm up just a bit. Revved it a bit and kicked it down off fast idle. Checked underneath....no oil leaks. Took it for a 5 minute drive. Got back in the driveway. Turned it off and off course, no surprises. Oil drops hanging from the inspection plate. I didn't even get mad. I just went in the house. The vacuum line work did not help anything but my idle. I WILL NOT BE DENIED!
Went back out to the jeep this morning early. Got everything to do this job that I know so well again. I climbed underneath. Pulled the starter and then the inspection plate. I just stopped right there and looked all around up in there as best I could. This is strange. The whole back of the removable inspection plate was dry. The whole back of the inspection plate that you cannot remove was dry. Both sides of the inner bellhousing as best as I could get my fingers in there was dry. Inside the starter wole in the bell housing was dry. Every piece of the flywheel that I could see was dry. Obviously the side that is facing the motor. I ran my finger on the inside bottom of the bellhousing where the inspection plate bolts up right under the toothed edge of the flywheel. There was a nice little puddle of new oil just waiting to come out. Everything around the rear of the oil pan where it mates to the bellhousing and rear cap was absolutely dry. The bottom edge of the crank rear that I could see was dry. If its the rear main seal or the rear oil pan gasket, why is it not showing absolutely any signs on the face of the flywheel or on the rear of either inspection plate? It would have to be wet or even SLIGHTLY if it were coming from the seal or oil pan gasket. The thing is, over these last few times going back and forth in there I do see the oil not leaking as bad as when I originally started this. I begin to wonder if the front seal on my tranny is leaking. How else could the oil be leaking from the inspection plate only and not getting any of the other surfaces wet I discussed. I just cannot see a cross-section of the tranny and motor in my head to know if there is a path for gear case oil to get to the inspection plate. If it is indeed gear oil from my tranny, then I am assuming my new clutch job is slowly going to again.
Any ideas on how to know for sure if it is gear oil? Smell? Viscosity by feel? Check the quantity of oil that would drain from the tranny? Yeah , yeah, yeah....Pull the motor huh?

Please let me know what you think guys.

Sid

 

[cityjack]

Xmas came early. I found the source of the leak. Kudos to the gentleman who asked....are you sure you don't have a tranny leak. Due to my newness with these CJ's and my rush to judgement I learned a long hard lesson. Actually a bunch of them.
Anyway, it is gear oil that is leaking from the front seal. I just got one from NAPA today and have the motor already disconnected. I'll hook the chain to it tomorrow and yank it out. Question or two if I may please. Anything in advance I should know of to replace this seal? All I have is a Haynes and you guys. Do I just remove the front bearing cap with the four screws and pry the seal out of the back and replace and reinstall the cap? Any orientation of the front cap or special tools or is there anything going to pop out at me after I remove the front cap?

Thanks guys for all of your help and ears.

Sid

 

[Rescue Diver]

Xmas came early. I found the source of the leak. Kudos to the gentleman who asked....are you sure you don't have a tranny leak. Due to my newness with these CJ's and my rush to judgement I learned a long hard lesson. Actually a bunch of them.
Anyway, it is gear oil that is leaking from the front seal. I just got one from NAPA today and have the motor already disconnected. I'll hook the chain to it tomorrow and yank it out. Question or two if I may please. Anything in advance I should know of to replace this seal? All I have is a Haynes and you guys. Do I just remove the front bearing cap with the four screws and pry the seal out of the back and replace and reinstall the cap? Any orientation of the front cap or special tools or is there anything going to pop out at me after I remove the front cap?

Thanks guys for all of your help and ears.

Sid

Glad you found it! Live and learn. Gear oil has a nasty smell to it that's usually pretty easy to detect. Be sure and replace the gasket that seals the front cover(thing that the seal presses in to and the throw out bearing slides on), or you might be doing this job more than once too!

Also, just mark the position that the cover is clocked when you remove it and put it back in the same way.

You're pulling the motor to get to it? I would personally just drop the cross member, remove the shifters and pull the four bolts holding the tranny to the bell housing, and the 8 bolts for the u-joints and remove the tranny and Transfer Case as one unit from underneath. That way you don't have to unbolt the motor mounts, drain and remove the radiator and disconnect all the hoses, unhook the fuel hose and all the wiring, and unhook the exhaust(unless it's in the way of getting the tranny physically out). Plus you don't have to worry about banging up your grill and fenders, or scratching your paint.

It just depends on which work you'd rather do.

 

[IOPort51]

I don't know what Transmission you have but marking the front seems like a good idea.
dropping tranny orr pulling engine, your choice, I like to pull the tranny, not so many wires and hoses to contend with. I will suggest that you drop the Transfer Case and Transmission as two pieces. As one unit it is quite heavy and very difficult to balance.

 

[Rescue Diver]

I don't know what Transmission you have but marking the front seems like a good idea.
dropping tranny orr pulling engine, your choice, I like to pull the tranny, not so many wires and hoses to contend with. I will suggest that you drop the Transfer Case and Transmission as two pieces. As one unit it is quite heavy and very difficult to balance.

The reason I suggested dropping it as one unit is it can be pretty difficult mating a tranny to a Transfer Case and getting some bolts started without ripping the gasket, even when they're both out of the Jeep and on your garage floor. Especially if the Transfer Case is a Dana 20 with the texas shaped bolt pattern. I'd rather fight with installing the whole heavy, hard to balance assembly than try and correctly clock and bolt the Transfer Case to the Transmission laying on my back if I can avoid it. But that's just me.

 

[cityjack]

Hey guys,

Quick couple of questions. I got the new seal pressed into the bearing cap already and am almost ready to put it back together. The original bearing cap gasket is in good shape with no tears at all. I was not able to get a new gasket in time seeings how my garage time in buddies place is Limited . The original gasket is paper thin. I have all kinds of sheets of gasket material to make another of my own. Only thing is, the gasket material I have is slightly thicker. The haynes book says to put some gasket sealer on the tranny face before putting the gasket on and then the bearing cap. I was going to use the same gray Permatex that I was using on the RMS. Do you think the thicker gasket material will cause a problem? If the original gasket is in good shape and I use gasket sealer do you think that will suffice? DAMN, that little spring next to the face of the bearing cap was a pain to get out of the way so I could remove the bearing cap.

Thanks guys. As soon as I get some feedback from you guys I'm back to my buddies.

I'll let you all know how it went.

Sid