Holy Hannah (rear main seal blew)

T-Rex Jeepster

T-Rex Jeepster

The Unoffendable
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Middle Tennessee
With about 9,000 to 9,500 on the rebuild I did on the 1994 4.0...The rear engine seal has gone to bleeding out a quart every 50 miles. I mean it blew like a switch got flipped. I'm wondering if the Amsoil change I did with the high end synthetic 10W30 and the 20,000 mile filter that looked awful short to me took it out. I did see about a 10# increase in the pressure from plain fossil oil. Well...Is there a "Superior" Rear seal? I think I went with a Fel-Pro but I could be wrong about that. Damn, Just when I had all the bugs worked out and she was runnin' like a watch.

But like a Buddy mine of said...."They always run best just before they blow". I'm really bummed over this one.....:cautious:
 
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max oil pressure is 75 the pumps relief valve opens at 75. the oil only goes to rear main and rear rode not to the seal direct.
par is 40
breather (x2) blocked, PVC valve blocked.
most rear main seals are best put in using RTV or thread locker.
chapter 9, all real filter have build in bypass if the filter ever clogs, surely you do not run oil for 20,000 miles, right?
and warning page 9-49
CAUTION: The felt lip must be located inside the flywheel mounting surface. If the lip is not posi tioned correctly the flywheel could tear the seal up.
I RTV mine in, so of breather cogs, only the front seal pushes out ;) is the air intake stock , all stock 2 hose PCV system???????
mine is stock and the PCV hose fresh air side is huge, no way to block that, short of dead mouse inside it. GOT THOSE crazy COLD air kits here?(mines trash canned)
The pump incorporates a nonadjustable pressure
relief valve to limit maximum pressure to 517 kPa
(75 psi). In the relief position, the valve permits oil to
bypass through a passage in the pump body to the
inlet side of the pump
Click to expand...

the 4.0L 9-91
has 2 piece seal. viton
read page 91 carefully, and the 914 sealant steps

4.0L
(7) Position the lower seal into the bearing cap recess and seat it firmly. Be sure the seal is flush with
the cylinder block pan rail.
(8) Apply Loctite 518, or equivalent on the rear
bearing cap (Fig. 8). The bead should be 3 mm (0.125
in) thick. DO NOT apply Loctite 518, or equivalent to
the lip of the seal.
(9) Install the rear main bearing cap. DO NOT strike
the cap more than twice for proper engagement.
(10) Tighten all main bearing bolts to 108 Nzm (80
ft. lbs.) torque.
(11) Install the oil pan gasket and oil pan
Click to expand...
 
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pan leaks rear
the 1999 model has new seals. make sure to get the right one.

if you look at that, the first thing that comes to mind are, beside pan leaks
is seal 4 ends how can those seal right?
the seal slit V , slit side is the engine pressure side. or it will leak like sieve.


see this video,, note the RTV step.

 
T-Rex Jeepster said:
Can you elaborate where that is and how to clean and check for flow?
Click to expand...
I have the '92 2.4L engine and I'm not sure about the 4.0L. This can be a common problem with older and new car when excessive pressure builds up in the crankcase and causes seals to leak or fail. On my 2.4L there's a small brass fitting inside the valve cover under on of the small towers and it has a small hole drilled in it. It's not a valve and can become plugged. I wish I had a phot of mine because it was covered over with 1/2inch of sludge.

1704147743113.png
 
Flyer58 said:
I have the '92 2.4L engine and I'm not sure about the 4.0L. This can be a common problem with older and new car when excessive pressure builds up in the crankcase and causes seals to leak or fail. On my 2.4L there's a small brass fitting inside the valve cover under on of the small towers and it has a small hole drilled in it. It's not a valve and can become plugged. I wish I had a phot of mine because it was covered over with 1/2inch of sludge.

View attachment 122360
Click to expand...
Everything is clean internally. Good oil intervals with Wix filters. The timing with this AMS-Oil thing has me wondering. Gonna go over the CCV system along with the charcoal cannister to make sure we're ventilating properly. I just had some surgery and have a few weeks to before I can get to it, So I'm going back with a Mopar OEM seal and a new oil pan and fel-pro gasket. Thanks for the feedback...
It makes it easier to settle down and get back in the right mind set to Get 'Er Done........
 
T-Rex Jeepster said:
Everything is clean internally. Good oil intervals with Wix filters. The timing with this AMS-Oil thing has me wondering. Gonna go over the CCV system along with the charcoal cannister to make sure we're ventilating properly. I just had some surgery and have a few weeks to before I can get to it, So I'm going back with a Mopar OEM seal and a new oil pan and fel-pro gasket. Thanks for the feedback...
It makes it easier to settle down and get back in the right mind set to Get 'Er Done........
Click to expand...
When you have the leaky seal out take a good look at the surface on the crankshaft the seal runs on. Prior to rebuild mine had a groove worn in it. If there's a groove you may need to tap on a speedi-sleve. I've used them several time and they've always worked.

1704152942756.png
 
T-Rex Jeepster said:
and gaskets are all new
Click to expand...
so at the rebuild the crankr rear end journal seal surface is all clean and no rust , not all grooved out.
who did the rebuild, so ask them to fix it?
the first part of any engine rebuild is a full careful inspection. for sure all journals.
was the crank shaft, turned? at the machine shop? tell what rebuilt means.? new bearings, sized how, to old crank sizes. or a turned crank.
if the crank was turned and polished as the all do, then the seal surface is now like new, see how that plays out?
The seal has step with RTV did you see that in the FSM (free factory service manual in the sticky)>
use the upgraded seals from Felpro or from ebay. parts used matters. felpro pan gasket is bar none best. ok?
all you know ,now is the rear area leaks engine oil.
why only remains.
 
first off there are 5 paths to leak here,
rear valve cover, leaks
runs down back of engine to vent slot on top of bell housing down the back of engine to bell and fools the owner.
way 2 pan gasket leaks rear.
way3, rtv not used as the FSM told you ,at the bearing rear cap installed. per FSM
way4 seal is bad or put in wrong, (super easy)
way5 crank seal journal a wreck.

or the very rare, cast iron block , flaws, called porosity leaks. (or cracks)
use oil dye to find the leak with "UV" flash lamp. just like we do on HVAC R134a?

see the red arrow here this is VENT, or OIL capturing slot? many cars have this with M/T not just Jeeps, other cars with M/T have this so cool air can reach the hot running clutch.

tranny just pulled.JPG


bell.JPG
 
there is no inspection cover here at B bottom. (o_O to see if oil is on what side of the clutch.
the air port will leak to top of pressure plate I think. and fly both ways so is moot. only that is is matters.
use the dye in the oil make sure it is 10w-30 and not GL4 gear lube.
both oils in my jeep are tan colored. GL4 never stinks like GL5 does.
use the DYE first.
make sure wind-age effects do not fool the tech and move oil from front of car to rear, or top to bottom, as all cars made love to do.
use the UV lamp make 100 %sure the VC is not leaking for sure rear. valve cover. gasket, mangled as they love to go going on and cheaper brands of gaskets.
 
the VC for alum cover?
is not same as steel tin metal cover.!
so what is there now 94 VC cover right?
the steel cover must never be over torqued, or warps and leaks, as millions did.
no photos of top of engine, so.....
 
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