rear main dillema

ok so im in a little bit of a fix...

91 XJ 4.0 296,000 miles

the rear main is leaking like none other, and its dripping onto the exhaust creating a smoke cloud that follows my xj wherever it goes. I have to put a quart in almost every week. Besides this leak, the engine runs perfectly and so does the tranny. I have a few options...

1. Anyone up for a rear main party? Kinda like a lift party but a little more fun . It would be nice if i could go somewhere with air tools, or even a complete set of tools. This job is definately way over my head, so i would really need some help.

2. Pay a shit ton of money to have a shop do it.

3. Theres a (96?) XJ a little ways from my house that is in really good condition, 192,000 miles. I figure i could do a complete engine swap into my XJ(is the wiring the same?) I know what you're thinking, "why dont you just buy the 96 and be good to go?" Well, i really love my xj and i would love to make an awesome jeep using parts from both, using the 91 body because i like 4 door better than 2(who would've thought???:dunno: ) and mine is a limited with all the goodies such as leather seats, tranny cooler, blah blah. Plus i payed next to nothing for the 91, and with 296,000 miles and a leaking engine i don't think it would be easy to sell.

anyone have any ideas for me? I'm thinking either option 1(if theres some good samaritan on here thats willing to help me out, im located in south holland illinois. Whats in it for you?-a case of beer and possibly some cash.) or 3

thanks

It's a 2-4 hour job...

Biggest deal is scraping the old gasket off the pan...

It's also a little easier if the old seal isn't moving to loosen the the main cap...

It's also super easy if you have about 6" of lift...

You won't need a jack!

G'luck...

The job can even be done on a stocker - you just need to lift the front end until the axle is at "full droop" to clear the oil sump (I should know, I've done it a couple times...)

You'll not really need air tools, but you WILL need a slender brass rod to push the old upper seal half out (1/8" or 3/16" by about 4-6" long should do neatly.) DO NOT USE STEEL.

As far as the other XJ goes - why do you think I've got five? It's nice to have another rig to drive for parts...

5-90

d'oh:doh:

i think im getting rear main confused with head gasket. Because if rear main is the same thing as the oil pan gasket, i just finished doing that and the leaking continues.

sorry for being such a noob. see what i mean when i say im not too mechanically knowledgeable?

no...

the rear main and the oil pan are separate...

but you should go ahead and change the oil pan gasket as long as you have to drop the oil pan to access the rear main...

the rear main seal is underneath the last (rearward) cap on the crankshaft...

try a search in the oen forum....

you'll get lots of info and tips.

x2 on the brass punch tip

yeah thats what i thought but then you were talking about scraping the pan so i got a little confused. i understand now...

well like i just said, i replaced my oil pan gasket a few days ago and that was the biggest pain in the ass, and i don't want to tear the bottom end up again. You can say it'll be an easy job, but im guessing you have way more experience than me (i'm only 16)

http://tek-tonic.com/rearmainseal/
that's on a TJ, but the motor is the same. You won't have the girdle to remove in a 91.
You shouldn't have to pull the exhaust either, I think it's a little tighter on a TJ.
That article says to use a small screwdriver to pop out the upper seal. Don't, go and find the appropriate sized brass rod. One slip with a steel screwdriver and you could mar the bearing surface on the crank.

You should do it yourself.

You will NOT find a shop that will do it with that many miles, and if you do...I would not let them.

Rev

ok well here's what im thinking right now...

go look at the other jeep and if its reasonable pick it up. Swap engines. While my 91 engine is out, do the rear main seal since it would be a whole lot easier to do with the engine out. Drop the 91 engine in the 96. Maybe exchange rear ends (the 96 has an 8.25). Then sell the 96. im also getting all kinds of crazy ideas like experimenting with making bastard packs out of the 96 leafs, or maybe even stroking the 91 engine. Hopefully the other jeep is reasonable, so i can build the best jeep i can out of parts from both of them.

the 96 engine will just plug and play into the 91 right? Will it mate up to my AW4? please say yes...

edit:this thread is in MWC because i was thinking about option #1 as stated above, but its turning into OEM tech material. Moderators feel free to move it

91Limited said:

ok well here's what im thinking right now...

go look at the other jeep and if its reasonable pick it up. Swap engines. While my 91 engine is out, do the rear main seal since it would be a whole lot easier to do with the engine out. Drop the 91 engine in the 96. Maybe exchange rear ends (the 96 has an 8.25). Then sell the 96. im also getting all kinds of crazy ideas like experimenting with making bastard packs out of the 96 leafs, or maybe even stroking the 91 engine. Hopefully the other jeep is reasonable, so i can build the best jeep i can out of parts from both of them.

the 96 engine will just plug and play into the 91 right? Will it mate up to my AW4? please say yes...

edit:this thread is in MWC because i was thinking about option #1 as stated above, but its turning into OEM tech material. Moderators feel free to move it

Click to expand...

I am going to be candid here and say that, if you are unsure about doing a rear main seal, you had better think twice about doing an engine swap and some of the other work you are thinking about. A rear main seal would be rated "easy" in comparison.

Believe me, replacing the oil pan gasket will be a lot easier this time around. Repetition is exactly how people learn and become proficient at doing their own work. Learnig your Jeep by performing the smaller maintenance items will prepare you for the larger projects.

It's important for you to research this job by searching and reading some of the posts here. It will give you insight as to some of the problems you may encounter as well as tips in how to make the job easier. Get all your ducks in a row ... make sure you have all the appropriate tools (borrow if necessary) and parts ready. Have some of your friends come over ... thay can provide some support as well as be able to make a part run for you if necessary.

Don't be afraid to jump in and do the job ... being 16 yrs. old does not make you any less capable. You'll do just fine ...

Les

91Limited said:

Moderators feel free to move it

Click to expand...

Like they need your permisson!


Where are you located?

EDIT: Nevermind, I missed it.

south holland illinois, south suburb of chicago

of course the moderators need my permission. you see that black name and that massive post count? i own this place

LBEXJ-i see you have a lifted xj. you ever done a rear main on a stock one? Even during my recent oil pan gasket change i had the sway bar disconnected and both front shocks off, with two fairly large people standing on both of the wheels, and the pan just cleared the axle.

but if the 96 engine will plug and play into my jeep, isnt it just a matter of disconnecting everything, making sure i mark all plugs and wires so that i know where to hook them up, unbolt it from the motor mounts, and yank the thing out?

96 will not "plug and play" sorry. (I think )

After you do the rear main, you will think "darn...that was too easy"

Rev

(and I will move this thread for more visability)

91Limited said:

... LBEXJ-i see you have a lifted xj. you ever done a rear main on a stock one? Even during my recent oil pan gasket change i had the sway bar disconnected and both front shocks off, with two fairly large people standing on both of the wheels, and the pan just cleared the axle ...

Click to expand...

Yes, I do have a lifted Cherokee, and yes, I've done a rear main seal ... and so much more.

More importantly, I also have an 18 year old son and know when to say "Son, go ahead and do whatever you think is best." Good Luck ...

Les

No way in hell would I do an engine swap instead of a rear main...and I hated doing the rear main. You're talking about swapping a motor that has 192 on it? How do you think the rear main is in that thing? All the rear mains in the XJ's blow. It's a PITA but if you just did a pan gasket then it's not that much more. I'm the guy that just recently was in the midwest and did a rear main before leaving CO. I ended up dropping the pan again in St. Louis b/c I had a nasty leak and wasn't sure if it was pan or rear main. All jobs are way faster the second time around. And you've got help. I did the it solo the first time. It was much easier with freinds the second time around.

Replace the pan gasket. I would use RTV on the pan, then put the gasket on and zip tie where the holes are. Go drink a pop. Take 5-90's advice on driving out that old main seal. Also take his advice and soak the new seal in oil...it'll drive in easier. Get that new seal in the correct way, torque that cap down and you're ready to put the pan back in. Cut all the zip ties, and now the gasket will stay in place. You're home free.

You'll need to make an analysis regarding whether the '96 engine (OBDII?) will "plug and play" into the '91 (OBDI?). I'd think swapping all of the '91's sensors onto the '96 would probably allow "plug and play"--I don't really know what computer, etc are used on a '96, so it's impossible to simply say "yes" or "no". Believe me, changing the rear main seal will be a peace of cake relative to the engine swap your leaning towards. Plus the the '96 is high mileage, and should be rebuilt before installing.
Additionally, I'd say if your '91 is experiencing the normal blow by of a 4.0l with that kind of mileage (oil in the air box, etc), obtain a rebuilt short block, and replace your current engine.

xjbubba said:

You'll need to make an analysis regarding whether the '96 engine (OBDII?) will "plug and play" into the '91 (OBDI?). I'd think swapping all of the '91's sensors onto the '96 would probably allow "plug and play"--I don't really know what computer, etc are used on a '96, so it's impossible to simply say "yes" or "no". Believe me, changing the rear main seal will be a peace of cake relative to the engine swap your leaning towards. Plus the the '96 is high mileage, and should be rebuilt before installing.
Additionally, I'd say if your '91 is experiencing the normal blow by of a 4.0l with that kind of mileage (oil in the air box, etc), obtain a rebuilt short block, and replace your current engine.

Click to expand...

yeah it has blowby, and it leaks. I just don't know how much farther my engine will go. By the way, i checked out the other xj, its actually a 95, and the engine has 60,000 miles on it. I'm thinking about getting a rebuilt shortblock because my engine is getting very old. Oh, and i didnt say an engine swap would be easier, i just had this...

91Limited said:

Swap engines. While my 91 engine is out, do the rear main seal since it would be a whole lot easier to do with the engine out. Drop the 91 engine in the 96

Click to expand...

...idea running through my head when i saw that jeep for sale.

I think you understand the options available to you. You just have to way the cost/benefits of each, considering your mechanical capabilities and budget; good luck.

Just FYI.....I drove my XJ with a 1qt per 200 miles rear main leak for almost 2 years.

Rev

Just suck it up - replace the rear main seal and re-seal the oilpan gasket. Get the '95 and use it for parts or to run around. Gain experience working on one while driving the other, etc...