NV_CHEROKEE

Hey guys I just bought my Cherokee about a week ago and all was ok but I changed my oil yesterday and this morning after a drive and it sitting for about half hour I noticed a pretty decent sized oil stain on the driveway. It seems to be coming from the middle bolt on the bottom of the trans and its engine oil for sure. It only leaks after sitting for a while, no leaks while its running though and its always the same amount of oil and then it stops. I'm thinking rear main maybe? Its not the pan gasket or the valve cover gasket I inspected both pretty thoroughly. Has anyone else had this issue? It just showed up right after I did my oil change, I put some 10w-30 in it maybe swap that out for some thicker oil? Any knowledge on this or suggestions would be appreciated.

DeadCellM60

How did the little rubber seal look on the oil pan drain plug? Is the plug itself tight?

Radi

Check around the oil filter adapter and oil pressure sender- also the back side of the valve cover gasket if you didn't really fine-tooth that area. Those are common leak areas.

cruiser54

My money's on the oil pressure sending unit getting whacked when removing the oil filter.

Nicks90xj

clean the area real good to see where the leak is at. i thought my rear main seal was leaking but come to find out it was the rear of the valve cover leaking.

cruiser54

That's why I wrote this:

I'd be looking up above first, and VERIFYING the source of the oil leak yourself. Many mechanics, friends, and good old Uncle Bob love to tell you it’s the rear main seal. Has a catastrophic ring to it, doesn’t it? A simple leak at the back of the valve cover or other source could produce the same symptoms. You don’t need to be a mechanic to figure this out. If you have good eyesight, you’re good to go on your own. Don't jump on the RMS/oil pan gasket bandwagon just yet.

Almost any oil leak on your 4.0 is gonna drip from the RMS area for two simple reasons.
First off, the engine sits nose-up and any oil will run back to the RMS area. Secondly, the RMS area is also the lowest point on the engine. Simple physics and the old plumber's adage apply here. "$hit flows downhill".

Valve cover gasket, oil pressure sending unit, oil filter adapter seals and distributor gasket, in that order, have to be eliminated as possibilities first.
Revised 8-15-2012

Slugger

if it wasn't leaking before and its leaking now. maybe the oil pan bolt isn't tight enough? did you spill any oil while filling it up? might just be running down the block.

RatchetMaster10

I had a leak in the same area and with the same exact symptoms. It was my distributor gasket.

cruiser54

That's why I wrote up what I did in Post #6. Everybody, who doesn't own or have to pay for or perform your vehicle repairs, loves to poke their noggin UNDER the Jeep and come out bearing the false bad news that your RMS is leaking.

Kalali

I found out that I had a missing oil pan bolt right at the back near the seal area causing a slow leak.
Anyone knows the bolt size? Saves me the time to remove another one for sizing.
Thanks.

cruiser54

What size head?

NV_CHEROKEE

Thanks for all the input. Well I gave everything a quick once over just now and I eliminated the valve cover gasket, the sending unit, the filter housing and the distributor gasket its not coming from that side of the engine. Here are some pics of the exact location....

cruiser54

I think you know the answer now for yourself.

NV_CHEROKEE

Yeah I kinda figured thats what it was... I just thought I'd ask some of you guys who might have seen it before to confirm.

cruiser54

Basically, for the reasons given, if it's not all those other things, then it's the RMS.