Oil leaking out of rear main after new air cleaner ?

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Topic author
candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Oil leaking out of rear main after new air cleaner ?

Post by candymancan »

Maybe this is a coincendance.. but i put in 0-40w oil about 50 miles ago oil wasnt leaking. But just now i replaced my ugly air hat with a chrome one from edelbrock and the oil breather cap i put a vented cap on from edlebrock.. Looks nice but as soon as i got home the Jeep was leaking badly out if the rear main seal. It never did this until just now. I did replace the lower half of the seal and it stopped my leak i had ( couldnt get the upper one out)

So im wondering is it this oil or does it have something to do with the breather cap ? The old breather cap as you all know a tube goes to the air hat.. So im wondering if this allowed the engine to suck blowby out of the engine.

But i thought the pcv was suppose to do that. When i take the oil cap off i do feel sucktion when i put ny palm on it. So it seems the pcv is working right ?

So is it because of the cap or this 0-40 fully synthetic oil. Im not sure because it didnt leak with this oil for 3 days but it started leaking imediatly after this cap was put on
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
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Tatsadasayago
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Joined: Thu Aug 28, 2014 2:22 pm
Location: Sacramento, CA

Re: Oil leaking out of rear main after new air cleaner ?

Post by Tatsadasayago »

I suggest you warm the engine up, remove the filler cap and bring the RPM up to about 2500 while watching for vapor/blow-by. It's possible the vented cap is too restrictive and is allowing crankcase pressure to rise. Keep in mind that as vacuum drops (under acceleration) the PCV is less effective.
1977 Cherokee Chief - The Blair Jeep Project III
A collection of parts flying in close formation

Topic author
candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: Oil leaking out of rear main after new air cleaner ?

Post by candymancan »

I put the old air filter on and old air cap back on and drove to the grocery store. Oil leak stopped.

So i dunno if thats a coincedance or what.

Bht i took the oil breather cap off fwlt again with my hand and its deff sucking in air.. I thrn took a thin plastic bag and removed a chunk of it so its just 1 peice of plastic and i held it over the oil filler tube and while holding the plastic i revved the engine on the carb to probly 1500 rpm and it wanted to suck the bag into the oil filler tube lol.

So i dunno
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

Topic author
candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: Oil leaking out of rear main after new air cleaner ?

Post by candymancan »

Hahaha i foubd my old thread... see i knew i remembered that this edlebrock air hat and edlebrock cap caused my oil leak.

So i wonder if this is why my im still plagued by my rear main leaking. I think ima route a line from a fsctory oil fill cap to my edlebrock air hat.. and see if this stops the rear main from leaking.

Or maybe i can find my stock air hat and put that back on. And see if this fixes the rear main leaking.

I knew i remembered this causing a major oil leak i just forgot about it
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)

sierrablue
Posts: 1208
Joined: Wed Nov 30, 2022 8:02 pm
Location: MN/CO

Re: Oil leaking out of rear main after new air cleaner ?

Post by sierrablue »

https://minneapolis.craigslist.org/wsh/ ... 43296.html

^Get the blue one of these and call it done :)
'71 Wagoneer (DD)
-B350 (HEI, iron 4-barrel, Edelbrock 1406), TH400, D20
-'74 D44 front (nonpower discs)
-custom headliner
-Front shoulder belts (rears eventually)

viewtopic.php?t=23070

There are 2 major differences between new Wranglers and FSJs. FSJs are meant to be both utilitarian and capable, not just capable. FSJs are also rarely initially recognized as Jeeps by the average American.

Topic author
candymancan
Posts: 3652
Joined: Tue Mar 22, 2016 11:32 pm

Re: Oil leaking out of rear main after new air cleaner ?

Post by candymancan »

Thats what i have and thats when i noticed it started leaking
1998 Jeep Grand Cherokee 5.9L Limited 219k
1998 Jeep Grand Cherokee 4.0 I6 laredo 430k
1990 Jeep Grand Wagoneer 155k
1976 Jeep J10.. 85k(repaired)
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