Once and for all.. Is this my rear main or ??

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

Once and for all.. Is this my rear main or ??

Post by candymancan »

So seriously i took my inspection cover off to look... The crank shaft with the bearing cap is dry.. old crusty oil.. but nothing fresh. The flex plate is dry too. Behind my inspection plate is dry.

But the inspection plate on that 2 inch lip that slides inside and its basically inside is wet and rivers of oil.

The engine block on top with ny camera is wet but its old oil with coolant a bolt is leaking back there. So it isnt from up top.

Why is the crabk itself dey but the inspection cover is wet on top where it pushes in against the crank.

Is the inspection plate blocking oil from the rear main from splattering inside ? Via its lip that slides in against the bearing cap ?

Or is it my oil pan thats actually leaking ?? But if it were the oil pan wouldnt it be leaking on the actual oil pan as well ?

This is so very confusing.

Look how dry this crank is there where the flex plate meets up... How could the rear main be leaking if that were dry and not dripping like the inspection cover is ?
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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: Once and for all.. Is this my rear main or ??

Post by candymancan »

Okay... last shot... Would me removing the factory air hat and that breather tube on the air filler neck... Caused the engine to not ( breath ) correctly at high rpm ? I heared the pcv doesnt work at high rpm right ? So doesnt the filler neck breather start sucking blow by out through the intake ?

Maybe me removing that is making this constantly leak.. ? It only leaks at high rpms too.. not idle. And i sware i noticed my leak getting worse 4-5 years ago when i out the edlebrock open air hat on and just a edlebrock cap on the oil filler tube. Maybe im wrong though.

What do you guys think ? Does that oil filler to thr intake help with pressure in the engine ? And i cut it off basically to an open air system
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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tgreese
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Joined: Fri Jun 08, 2012 6:31 am
Location: Medford MA USA

Re: Once and for all.. Is this my rear main or ??

Post by tgreese »

Think of what you can easily test or measure.

If you don't mind putting your lips on the underside of the breather, you could try blowing through the breather. (Grimy but not germy). I suspect your breather flows easier than the original part. Or buy the original part, put it on there and see if the leak changes. https://www.bing.com/search?q=3220248+Jeep

Previously I suggested the dye and UV light kit.
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.

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

Re: Once and for all.. Is this my rear main or ??

Post by sierrablue »

Feel free to correct me if I'm wrong, but from my understanding, the PCV has little to do with RPM and more to do with vacuum. If you have a LOT of vacuum, at idle or whatever, the metal in there may be sucked clear to the top, and with no vacuum (WOT), it may sit in the bottom.

However, it's just that it "may" do that because the crankcase pressure it's bleeding off will be changing. There may very well be enough crankcase pressure to push it open at WOT, and there may be not enough vacuum to suck it all the way up at idle.

This is just my understanding of it; I may very well be wrong. But based on what you said, to me it sounds more like it seals up fine under low amounts of oil pressure, and as you go up in pressure it starts to leak. Not really sure what would cause that, other than maybe a seal that seals up ok but not perfectly.
'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.
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tgreese
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Location: Medford MA USA

Re: Once and for all.. Is this my rear main or ??

Post by tgreese »

Other possible sources of oil in that area:
00) valve cover gaskets (dye test)
0) oil pan gasket (dye test)
1) manifold seal to the top of the block. (dye test)
2) cylinder head gasket. (leakdown test? dye test?)
3) oil gallery plugs on the back of the block (dye test?)
4) front transmission seal (sniff? color?)
Tim Reese
Maine beekeeper's truck: '77 J10 LWB, 258/T15/D20/3.54 bone stock, low options (delete radio), PS/PDB, hubcaps.
Browless and proud: '82 J20 360/T18/NP208/3.73, Destination A/Ts, 7600 GVWR
Copper Polly: '75 CJ-6, 304/T15, PS, BFG KM2s, soft top
GTI without the badges: '95 VW Golf Sport 2000cc 2D
Dual Everything: '15 Chryco Jeep Cherokee KL Trailhawk, ECO Green
Blockchain the vote.

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

Re: Once and for all.. Is this my rear main or ??

Post by candymancan »

sierrablue wrote: Sun Mar 26, 2023 8:57 am Feel free to correct me if I'm wrong, but from my understanding, the PCV has little to do with RPM and more to do with vacuum. If you have a LOT of vacuum, at idle or whatever, the metal in there may be sucked clear to the top, and with no vacuum (WOT), it may sit in the bottom.

However, it's just that it "may" do that because the crankcase pressure it's bleeding off will be changing. There may very well be enough crankcase pressure to push it open at WOT, and there may be not enough vacuum to suck it all the way up at idle.

This is just my understanding of it; I may very well be wrong. But based on what you said, to me it sounds more like it seals up fine under low amounts of oil pressure, and as you go up in pressure it starts to leak. Not really sure what would cause that, other than maybe a seal that seals up ok but not perfectly.

My pcv sits sideways. Not up or down ? Should it be pointing up ? The way its made it looks like it should be sideways like it is. But im not sure.

Its like a t fitting pcv. Small vacuum ljne on it goes to a cto i think or maybe the charcial canister ? I csnt remember off hand.. and it lays sideways.. one end nearly directly in the csrb. Thr other hose turns left into the intake.

Ya i blew into the open air oil cap.. it blows free. I breathed into the pcv line in the intake too.. its free. Pcv is super clean it does rattle at idle though. Can even hear it in the cabin.

Yes it can idle at 1000rpm in park for hours.. and never leak. But at 2000rpm. Itll leak.


None of the dang auto parts stores have the fsctory yellow oil breather cap. I was gonna run a line to my edelbrock air cleaner like factory and see what happens. Im just curious is all.

So i gatta order it online.. couldnt find mine in my parts anywhere.

I need to pull and luah my bakencer like people keep telling me... I dunno if its thst though as my bearings were in such good shspe.

I also discovered two upper transmission bellhousing bolts ti the engine are so lose the washer can pivot.. i gatta figure out how to get a socket back there and tighten 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: Once and for all.. Is this my rear main or ??

Post by sierrablue »

I dunno how they're supposed to sit on the AMCs. On the Buick, it plugs straight into a grommet that's vertical in the back of the intake manifold, and then the hose runs to the front of the carb from the other end of the PCV obv.

Kinda sucks that you have to order that. I suggested the blue cap because it's an AMC cap, so if flow is an issue, it should be designed for the AMC, with exactly the flow/resistance you need.
'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.

letank
Posts: 4009
Joined: Wed Oct 03, 2012 9:16 pm
Location: SF bay area

Re: Once and for all.. Is this my rear main or ??

Post by letank »

candymancan wrote: Sun Mar 26, 2023 7:26 pm
My pcv sits sideways. Not up or down ? Should it be pointing up ? The way its made it looks like it should be sideways like it is. But im not sure.

Its like a t fitting pcv. Small vacuum ljne on it goes to a cto i think or maybe the charcial canister ? I csnt remember off hand.. and it lays sideways.. one end nearly directly in the csrb. Thr other hose turns left into the intake.
here is my PCV, it is up and goes straight to the canister

Image

Image
Michel
74 wag (349 Kmiles... parked, next step is a rust free body)
85 Gwag (229 Kmiles... the running test lab)

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

Re: Once and for all.. Is this my rear main or ??

Post by candymancan »

Thats a small line to the charcoal the actual pcv rattler thingy part is sideways to the intake.
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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