Is then back of the block behind the flexplate clean and dry as well? It could possibly leak down the block and miss the flexplate. If it isnt coming from the rear main, the next best guess would be the valve covers. And they would typically leak onto the exhaust manifolds directly, which would smoke and stink too.

 

@Bigrigr
I'll take a look, but I doubt it as the trans structural cover was clean and relatively oil-free on the inside.
Upon closer inspection, the oil appears to be coming from the passenger's side valve cover, which I will attempt to change out today.

P.S. Has anyone ever pulled the 4.7 oil pan......AND KEPT THEIR SANITY ?!?! Mine was the original seal and I swear it was welded to the gasket which was welded to the block. Was not fun.

 

P.S. Has anyone ever pulled the 4.7 oil pan......AND KEPT THEIR SANITY ?!?! Mine was the original seal and I swear it was welded to the gasket which was welded to the block. Was not fun.

Lol yeah mine was the same. I thought for sure I was breaking something. Lucky for me I had a friend nearby with more experience who jumped in when I was losing my mind. The rear of the pan just did not want to come off. Bent up the pan a little getting it off and had to straighten it out with some strategic hammering.

 

Mine, and 04 4.7 ho does the same thing, oil down onto the cats and smell terrible when i shut it off. Trans covered in oil too from it. But it so slow it never lowers the dipstick between changes so I have been putting off changing the rear main seal because you have to pull the transmission to do it.
I felt around the back of the heads, did not get any oil on my hands so I always assumed it was the seal. Maybe I'll bet out my insection camera and see if the valve covers are leaking which i doubt as i could not see any oil on them.

 

@Darnice
Perhaps just pull the Structural cover (8 bolts) off the bottom front of the trans housing and take a look.
Relatively easy to do and costs nothing.
Now that I think about it, I said 'relatively easy' probably because I had pulled my entire exhaust out. It might be a bit tight with the exhaust in place.

 

I believe you need to drop the exhaust from the manifolds to get the structural cover off. It is pretty tight in that area even with the pipes released but it can be done.

 

Before starting a job like that, check the easy things first - are the valve cover gaskets leaking down? Has the pcv blocked up with mayo causing excess crank case pressure forcing the oil out?

On my first 4.7 WJ I thought the rear main seal had gone, but the pcv was gunked up due to the mayo build up on winter short journeys. Cleaned it out regularly after that and no more leaks...which was nice :smile2:

 

I have the same problem with my 04 4.7 where oil drips on one of the smaller cats particularly when parked uphill at the bottom of my drive. I know the valve cover gaskets are leaking some and have new Felpro gaskets to install.

But when I replace the valve cover gaskets I'm also going to check those emissions hoses with supposedly one on the back of each head. I've read from others on here where those hoses can split/crack then oil will leak out of them on the back of the heads and/or block. Some find so much oil in those hoses they install some type of catch-can system to collect it. Not sure if that's from the higher mileage WJ's but the condition of those hoses on the back of the 4.7 heads are something to check.

 

Agreed.
I have new PCV and CCV System on hand....just awaiting replacement.

 

Glad this post has come up and it has activity. I have the same issue with leaking oil down the back of the engine.
I swapped out both valve cover gaskets and the leak is as bad as ever. I'm likewise thinking it isn't the RMS.

I'm leaning towards the oil pan gasket. Do keep us informed on what you find out.

 

@Double E
My oil pan was definitely leaking also. Guess I don't blame it since it was the original (16 yrs / 135k miles )
Upon close inspection of the oil pan, it was obvious where some of the leaks were coming from.

IMO, the largest donation to my oil leak is originating from my Passenger Side Valve Cover. I am in the process of taking care of that as we speak. I've done lots of reading on this site wrt that process. Lots of good ideas / shortcuts which I may take advantage of. I'm going to try following the FSM, but really don't want to drain the cooling system (Step 7). so I'm currently to Step 8: Disconnect injector and ignition coil connectors. It's a bit of a challenge as those connectors are extremely brittle but I have most of them disconnected using a pick or small screwdriver.

Well....coffee break's over.....back to the garage!

BTW, I'm in no hurry to get this done, so time is on my side, but would like to finish it up by the w/e!

 

@Double E
If oil is coming down the back <top> of your engine and it is not the valve covers, the culprit I would suspect is the PCV / CCV system. The CCV runs across the back of the engine and, as many folks on the forum have commented, the rubber hose(s) is(are) disconnected / broken / cracked, etc. As Fzz stated in post #7....inspect and remedy the easy things first.

 

So, i tried to see this PVC system, Driver side, reach back ther and all was dry from what i could feel, valve cover not leaking for sure. Passanger side seem impossibe to get at from above, its the a crawl under and look up thing?

I'll try my inspection camera too, did not have time today.

 

Last night I replaced the CCV and PCV systems.

CCV hoses not cracked, not really brittle. On the driver's side, with the air plenum off, kind of laying on top of the motor, I was able to reach back with my right arm and, with much force, wrestle the hose off the head unit (Metal piece screwed into the head). On the passenger side, standing on a stool /laying over the fender and reaching in deep with my right arm, I was able to wrestle (again with great force and patience) that hose off. I removed the CCV hose from the driver's side. For the replacement CCV, I lubed up the inside of the hoses, fed it back through the driver's side (again, patience) and using similar positions/technique for removal, was able to position R/L hoses on the metal pieces screwed into the head.

When i went to remove the PCV tube, it just pulled right out the passenger side (with no effort whatsoever) and the back side didn't have a rubber hose connected. Again, I laid over the passenger side of the engine and felt around the back of the intake for the connection point. It seemed to be immediately behind and relatively high on the back of the intake. There was nothing connected. Not sure where that little 90 degree hose went, but it wasn't there. Nonetheless, I fed the new PCV tube back thru the passenger side and after some finagling, I was finally able to attach the hose to the intake nipple. Needless to say, I was done for the night. I will go back out this afternoon and, using my remote camera, take a look behind the intake to ensure everything is properly connected.....and maybe even locate that mysteriously lost little 90 degree rubber hose!

wRT Passenger Valve Cover Removal: I've removed, unhooked, dismounted & re-positioned all components required to start removing the bolts on the passenger valve cover (I did not drain my cooling system nor did I disconnect the heater hoses). The rear-top bolt appears like it's gonna be a bit difficult. Any hints???...looks like it's gonna take some long extensions with a universal @ almost 90 degrees to remove it. Additionally, I compared the location of my stud bolts to the 'indicated' location in the FSM diagram. For whatever reason, mine do not match up exactly with the FSM. Anyway, when I reinstall the valve cover, I will rearrange the stud bolts wrt to FSM diagram.

Stay tuned.

 

Some good info jstpeters and interesting about the missing little rubber hose. Do you think that may be part of your oil leak problems or is it higher on the intake where maybe the oil wouldn't be leaking so much?

Curious if you're going to put any gasket maker/sealer on the new valve cover gaskets? I was thinking about putting some ultra black just on the corners, particularly the lower back gasket/corner. I've heard others say this is where you may develop another leak even with a new gasket.

 

That battery, alternator and grounding wiring harness for the passenger side is a bear. Remember to re-connect (seat) the TCM connectors on the firewall well. They tend to fool you into thinking they are connected.

Those PCV hoses do not get a lot pf pressure so that they were not connected well is not a surprise. Mine are definitely not optimally sealed but not leaking oil either.

I didn't drain my coolant. I've done this VC gasket change on 3 WJs now and have not had to do that yet. My guess is that the FSM says to do it so you can remove the heater hoses. They will move out of the way still connected as you probably found out.

 

@Uniblurb
I have also read the posts on the gasket sealer. Not sure whether I'll do that or not.
Since Double E is a veteran of 3 of these operations (I'm a rookie) let's get his take.
@Double E
Any input on gasket sealer?
To address your comments: I did not disturb/remove the alternator or the grounding wire harness, nor did I disconnect the TCM or PCM harnesses. Perhaps I should have, but thus far I have been able to work around those items. Although, with those items removed/released, I'll bet it frees up a crap-load of space to make the job a bit easier. Since my exhaust system is currently removed, I may take a look at releasing the grounding wire harness. I would bet this will make it so much easier getting to the back/rear side of the valve cover. As a bonus, I could probably clean up the ground point at the same time.

Last night I was able to unbolt and remove the passenger valve cover. A bit tedious working it out of its cocoon, but not too terribly bad.
As I was looking at the FelPro grommets for the valve cover bolt holes, I said to myself "these are never gonna work, they're too pliable!". After I inspected one of the valve cover bolts and determined that I could not remove the bolt from the little metal spacer, it dawned on me that perhaps the Felpro grommet was not a stand-alone piece, but actually a 'replacement' grommet for the black grommet that resides on each of the bolts. So I punched one of the bolts out of the valve cover, put the head in a vice and, utilizing a razor cutter, sliced and removed the original black grommet (hard as a piece of plastic) from the bolt. I put a bit of oil inside the FelPro grommet and, WALLAH, it slid right on there. So....I felt like an idiot for not realizing this from the get go. Live and learn, I guess. I repeated this process for the remaining bolts and studs. I removed the old valve cover gasket, cleaned the surface (to include the groove) real good, installed the new gasket (identified - passenger side gasket had an 'R' stamped on the little tab vs the driver's side gasket which has nothing stamped on the tab). I then reinserted the bolts/studs back into the valve cover following the FSM diagram.

I plan to reinstall the passenger side valve cover this evening. Then on to the driver's side!

 

Good deal. Sounds like you had the room you needed. Glad you figured out the grommets too. When I saw the harness going to ground points on the block, I did as you suggested and cleaned them up before reinstalling. I did use a light coat of gasket sealer all the way around on the head side on 2 of these jobs. I left the cover side dry. I didn't use any when I did this on my non-HO 4.7L 2000. It was leaking the worst of the 3 and it never leaked again afterwards.

Driver's side is a breeze but the back bolts are still no fun.

 

Installed the passenger side valve cover last night. I did not use any type of gasket sealer. It was a bit of a jig-saw puzzle getting in place. Some of the bolts/grommets decided to displace themselves during this process, so you can imagine the fiasco getting the back bolts in place properly. I checked the gasket all around with my remote camera just to ensure it didn't dislodge from the valve cover. The gasket appeared secure and properly in place after torquing all valve cover bolts to 105 in/lbs. This seemingly minor operation took me an hour and a half.....so I called it a night and will continue reinstalling all components tomorrow evening.

I checked the driver's side block and there was zero oil residue, so it appears the valve cover is sealing. But, and y'all will probably call me stupid/crazy/etc., since I have the FelPro kit, I am going to forge ahead and replace the driver's side gasket and grommets. The FSM says to "Disconnect the left side Breather Tube and remove the Breather Tube". **Is this really necessary?**

I've also decided to install new Crankshaft and Camshaft Sensors (MOPAR <Made in China>). It appears to be relatively straight forward with the exhaust removed. Will report if issues arise.

 

No, it's not necessary to remove the breather tube. Sometimes they seem to put extra steps in the FSM. Most of the time they make it easier, but the breather tube step left me scratching my head too.

 

Last night I changed out the driver's side valve cover gasket and grommets. I followed GmanWJ's advice and left the breather tube in place.
Only took me about an hour & 15 minutes to complete the entire side. As others have stated "A piece of cake compare to the passenger side valve cover!". One thing I did which the FSM did not state was to disconnect the three electrical connectors by the A/C compressor. One connector was for the A/C, I believe another is the MAF Sensor & not sure (can't visualize) what the other connector goes to, but it is exactly in the same neighborhood as the other two. Releasing these connectors allowed me to actually flop the entire driver's side electrical harness out of the way of the valve cover path.

Anyway, oil pan goes in tonight. Will report if I have any issues. I will then monitor engine oil leaks/seeps and report back in about a month.

 

Well, i spent little time looking closer at my rear seal leak, It not the Valve Cover gaskets or the breather system. They are both dry. Slight seapage on the passanger side valve cover but not enough to cause even a drip.
Where does the hard plastic line from the PCV valve on the oil fill to the back of the intake manifold go? (4.7 ho).Is it just plugged into the intake manifold at the back underneath the throttle body. Thats the only one i can't see very well.
Snowed here so crawling under will be postpoed until warmer weather, but it looking like the rear main seal. Which if it is, will just be left alone as it only few drops overnight and no adding oil between changes.

Had a brake hardline rust through though, lost rear brakes, got that fixed. 16 years of road salt takes its toll.

 

Where does the hard plastic line from the PCV valve on the oil fill to the back of the intake manifold go? (4.7 ho).Is it just plugged into the intake manifold at the back underneath the throttle body. Thats the only one i can't see very well.

@Darnice
The PCV line connects from the PCV Valve relatively straight back, takes a 90 degree turn and the rubber hose plugs into the back of the intake. If you take the air plenum off, you can reach around the right back side and feel the inlet <barbed pipe/nozzle?>. That's how figured out mine was disconnected.
It is located about center of the intake and a bit high. Just feel around back there with your right hand and you'll find it.

 

Recently bought an 04 JGC limited with the 4.7. With only 160,000 miles this thing is a box of leaks. I completed the valve covers first, thinking I can trace the leaking downward as I go. I highly suggest the Felpro VC gasket set. Was a pain but that leak is now fixed. Good advice on diagnosing the possible RMS leak below that I will have to try.

 

Well, I'm inter-twining a couple of threads (new exhaust and an oil leak), so I'll try to get back on track with the oil leak.

So this adventure started with oil leaking on the cats...suspecting the rear main seal as the culprit. After removing the exhaust and transmission inspection plate, I didn't' see any evidence of oil in the bell housing and the flex plate appeared dry. Anyway, with that info, I proceeded to replace Valve Cover Gaskets, CCV System, PVC System, Oil Pan, Oil Pan Gasket w/baffle, entire Exhaust System (-)manifolds.)
After completing install of all new parts, I ran the vehicle for about .5 hrs. She started right up, ran/idled perfectly, no warning indicators and, needless to say, I sighed a breath of relief !!
The next morning I checked underneath for any leaks, etc.

I noticed an oil drip 'indication' originating from the passenger side bolt (horizontal bolt - connects tran insp plate to bell housing) on the flex plate/bell housing side of the bolt with oil dripping onto the top of the cat and 'streaking' around to the bottom of the cat, leaving a nice big drip <just waiting to fall>. The oil leak was not coming out of the little hole/opening in the underneath/middle of the the bell housing.

The oil is definitely (and after thorough inspection, positively) not coming from anywhere outside the bell housing.
It just puzzles me that if it were the Rear Main Seal, why is there no sign of oil dripping thru the little opening at the bottom of the bell housing.

So it's back to the drawing board.
Will report back whatever it is I find.

For The Record: I really do appreciate everyone's input/advice/thoughts. Thank You!

 

Pictures wrt the above Post.

 

Yup. Oil leak confirmed. Hope you find it so the rest of us can plug our leaks too!

 

I know for a fact that if oil is leaking from the valve covers or heads into the valley between the heads it will run down the back of the engine and out through the gap between the bell housing and structural cover. So, it may only look like a rear main seal leak. In reality, on many 4.7's of WJ vintage, most of it is probably coming from the valve covers and only being supplemented by the rear main seal.

Of course, anything leaking into the valley is completely obscured by the intake manifold.

Supplemental anecdote --- after I rebuilt the engine in the white WJ in my picture, it cranked up and I drove it about 10 miles. The whole time I had white smoke (it was burning coolant) and when I got home I looked and there was a HUGE amount of oil all over the bottom of the bell housing and structural cover. Needless to say, I was super distraught. I ended up assuming that I had either misaligned the rear main seal or, worse, I didn't get the RTV applied properly between the block and the bottom skirt/girdle.

After I pulled the engine back out and removed the intake manifold, there was a big puddle of oil in the valley between the heads. On the contrary, where I thought it had been leaking at the back of the engine between the girdle and the block and around the rear main seal was all completely dry. So the whole problem was that I did NOT torque down the heads sufficiently enough. Oil leaked into the valley and coolant into the cylinders!