need input - CJ oil leak

fattypackard

fattypackard

Well-Known Member
Joined
Mar 20, 2005
Location
VA Beach
here is a picture of basically where the leak is coming from.
from what i can tell it is leaking where the tranny bolts to the back of the engine block. thus making me think its either a rear main seal OR the tranny gasket.
a small puddle always builds up after sitting for about 10 minutes after a drive in the CJ, right below where the tranny bolts to the engine.
my questions are 1) whomever has replaced a main seal or tranny gasket on a CJ...is there anything i should look for be prepared for?
and 2) with a leak that puddles up to about a couple inches in diameter after sitting for a few minutes, should i be really concerned and fix it asap or should i just watch the fluid level each week?
thanks for the advice
Picture098-1.jpg
 
I would try to clean it and let it idle/drip...

looks like you may be getting some blow back, that is catching and collecting on the bell housing and dripping from there.

Not ruling out RMS but pan is wet forward of mount point....
 
oh yea, getting blow back out of well...everywhere. hah

and actually, going through the files in the glove box...in 2001 my grandpa took it in because of oil leakage around the valve cover. the tech writeup from some dealership in rockingham said "exesive amount of blowback coming out everywhere possible...needs new engine"

engine runs perfect...i guess from sitting so long every seal in the damned engine is worn though.

the entire engine is damp to some degree. but there is no dripping at all under the engine, the only dripping is where i described.

so from that picture you think its a possibility that the fluid is oil instead of gear oil from the tranny?
 
looking under the jeep more and doing some research and thinking about what you said i think it is just a crap ton of oil being forced out as its being driven.

nor does it have that distinct gear oil smell...
 
not saying you dont have a tranny leak, but the pic DEFINITELY has motor oil on the tranny.
 
What engine? The 258 can have valve cover that is a pain to seal up, and if you get it to seal it won't last forever. A leak at the from the valve cover near the firewall will cover the tranny and back of the engine.

One thing to note is that tranny oil typically doesn't swim upstream, so if its on the engine as well it may not be the tranny.
 
^ you and skyhigh seem to have the same thinking. and it makes sense to me.

yes it does leake around the back of the valve cover. (around the whole thing really) but the left side of the engine and back of it are the most damp.
 
easiest to see where it's leaking by cleaning it. Something I have done in the past, and will sound funny, but, clean it real good. Let it dry, then coat it with baby powder. It really helps to show where it's leaking. Oh and yeah, you'll have a big puff once you crank it LOL
As said before, what engine? The 258's are well known to leak as you described. If it's an older 258 with a metal valve cover, it's easier to seal up. The newer ones with the plastic covers are a pita to stop leaking. Only way I found was a good amount of RTV and barely tighten it, let sit a a day or so, then snug the bolts on down, using locktight (blue) to keep them from backing out. Also if you do change the valve cover gasket, make sure the oil return holes are not blocked or restricted.
As far as blow by, might want to check your PCV, a new one is only a few bucks. If it can't breath then it'll increase the blow by you get. You can also change the oil, and use some Restore in it. It will help fill scratches in the cylinder walls and decrease the blow by.
No matter how much leaks out, as long as you keep the oil lever at the full mark, you won't have engine failure due to lack of oil.
An AMC 258 is similar to a Harley, you know it's out of oil, when it quits leaking
 
^ its an 83 258 with 92K miles (but like i said in another thread its been sitting for a good 5 years without being cranked)

and it was brought in to a shop a while back by my grandpa for valve cover leakage.

i'll try all of what you told me to do and see what happens. i've been using rotella 15 40 and lucas stopleak/oil stabilizer in it. and i've been checking the oil level every few days. it has gone down a LITTLE. not too noticeable though.

i cant remember right this minute but i think the valve cover is metal

anyways i'll try everything you said today and see how it goes! thanks for the tips upnover!

PS: i'll take a picture of the valve cover/engine in a little bit
 
ok went out and looked again. its a plastic valve cover (nice!)

and i also noticed that on the botto for the front end of the motor is some oil around the oil pan too...so that gasket is probably worn too and its leaking a little from there too.
 
this is the front end of the left side of the valve cover...
Picture100.jpg

this is the left side of the back end of the valve cover...
Picture099-1.jpg

and this is the right side...
Picture101-1.jpg
 
^ i can do that mike. maybe i can stop by this weekend, i'll let you know.

this afternoon i "somewhat" cleaned the underside. then i took the walve cover off, shaved off all the old sealant with a razor on the cover and the engine. the rear of the valve cover and the left side didnt seem to be sealed as well as the right side. then i put high temp RTV sealant on, put the cover back on and am now going to wait a good day before i put everything else back.

i put a new PCV on also. so hopefully this will help...
 
The next (less positive) area to check is the head gasket - passenger side. I've done all the above, valve cover, RMS, oil pan gasket, and I still get the top pic look on my CJ. I'm curious at what you come up with. Later, T.J.
 
^^ i dont really think i would trust that?

well the volve cover is done, now i just have to drive it around and see if the leaking is as bad.

i got an oil pain gasket too, but that will be a later project.
 
well........

i knew i could get some great advice from you guys.

turns out, the new valve cover gasket and PCV etc etc did the trick. i drove around today after re-cleaning the engine/tranny and as far as i can tell there is no more leak.

they may be some leakage still but not enough for it to leak onto the ground like before!

so thanks skyhigh and upnover for the tips
 
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