I need a little help with oil leak...
 

The oil pan around the top is dry it seem to be coming from inside. Is there a seal on the inside?

Rear main seal would be my guess if that's at the rear of the engine where it meets the trans.

No it's the passage side axle that goes through the oil pan. 3.0 motor.

I'd check your valve cover gasket out, the M54 is known to leak there especially when the CCV is starting to fail.

Also if you're having oil from the drivers side of the car it's probably the oil filter housing gasket.

Thanks. I just got it a couple weeks ago trying to get all the bugs worked out. I have a valve cover and the oil filter gasket I haven't installed them yet. I cleaned the motor up this passed weekend so I could see where the oil was coming from. It seems to be dry around the valve cover and the oil filter gasket but I am going to change then anyway. I will check around will a mirror this weekend and see if I can find where is coming from.

I wouldn't tear into it if you can't find the leak right away, it could save you some headaches. Just my suggestion lol.

How did you go with those leaks?
I had a simular leak and had to change the O ring between the bearing housing and the sump. I now have another leak in the same spot. would love to hear how you went.

Did either of you identify the source of your leak? I have the exact same leak and it is driving me crazy. I assume it's the pan gasket but would like to confirm before I tackle that job. Thanks!

There's an o-ring seal behind that axle housing. you need to remove the drive axle and four bolts will get the axle housing off. While you are at it replace the differential seal that the drive shaft runs through.

You know I thought that, and it would make sense as that is exactly were it looks like the oil is coming from. However I was under the impression the axle runs through a cavity in the oil pan that is dry, so I'm not sure were the oil would be coming from if it was making it past the o ring. I don't see any oil between the pan and block and it is definitely not coming from up top. Heck there isn't even any oil on top of the support bracket. It just keeps accumulating at the bottom exactly like the picture in the first post.

Here's a picture of the axle housing and the o-ring that I referred to.

http://www.leebmann24.de/media/catal...2/127416_1.JPG

Item 8 is the o-ring. but you should also replace the seal item 7 while you have it apart.

That's not engine oil that is leaking out, but differential oil.

I'll have a look but gear oil has a very unique color, viscosity and smell. All of which this doesn't have. I'll 99% certain it's engine oil.

http://www.xoutpost.com/attachments/...il-leak-1-.jpg

The location of the leak base upon the Original Poster picture is probably the o-ring between the oil pan and the axle housing. The cavity in the oil pan through which the axle passes through is not DRY. The cavity is filled with differential fluid. If the cavity was dry, there will be no need for an o-ring or seals at the axles.

I am also having a "mysterious" leak in the same location. Over the weekend I cleaned everything off and then let the motor run for a while and rev'd the engine. did this a couple times and no leak. Then drove the car a little and the leak was on the garage floor. Mine is dripping off the housing and through the first opening in the metal skid plate. My only concern is that I thought differential oil is incredibly smelly and me and my wife (she was very pleased when I asked her to smell my finger) thought it didn't smell. I pulled the dip stick and we both concluded that the oil smelled completely different. Is there any other way to verify motor oil vs. differential oil? Or am I over thinking this and should I just replace the seals?

I do not recall any discussion of the engine. If the M54, then the valve cover gasket is high on the list of usual suspects. Oil can run down the side of the engine and drip off of anywhere that is a low point. Having said that, the oil from the valve cover gasket typically falls onto the exhaust manifold.

On second thought, I agree with the diagnosis of the O-ring that the others have called out.

I might crawl under my X5 and look at this. My car is dripping small drops on the garage floor, about the size of a dime or a nickel.

It's the 3.0. I'm going to pull the fill plug in the differential and see if the oil is the same before pulling the axle and replacing the seal and o'ring. The oil leaking is very clean (just changed my oil) so I'm skeptical but there is no oil anywhere around this support...only the oil leaking from the bottom. Strange indeed.

Diff oil has a *very* distinctive smell, even a tiny amount stinks from the sulphur content. If you can't smell it, it's engine oil. Diff oil is also thicker and slipperier(made that word up, lol). My bet is this is engine oil.

Differential oil is used to lube the crown and pinion gears, engine oil is used to lube the crank and cam bearing, but because it is exposed to the heat of combustion and contaminated with combustion gases, the engine oil over time turns black and must be renewed on a regular base. If you look at the picture, the oil is still fairly clean.

Sorry to jump in on your thread OP, but I am having the exact same leak.

Everyone says diff oil should "stink" but I didn't think it smelled that bad. When I pulled the dipstick the engine oil smelled different than what ever fluid was on the ground. I just changed my oil (maybe 60 miles) so the color is very similar. Is there any way to be sure which fluid it is. Mine was also running out of the whole and along/down the bottom of the oil pan, so my first guess was leaky oil pan gasket.

The old fashion Hypoid gear oil in days gone bye stunk really bad, but the new synthetic oil doesn't stink as bad.

Hmmm... every synthetic GL5 gear oil I've ever used (Mobil 1, Redline, Amsoil, Royal Purple) smells foul. The difference between motor oil and gear oil in terms of smell should be obvious. If it doesn't reek, it's motor oil.

Typically been my experience as well. Not a HORRIBLE smell... but definitely not the same as regular motor oil.

The fact that the oil is leaking from the same location as in the picture and the fact that both you and your wife were able to determine that the engine oil was not the same smell as the oil on the floor, that will leave you to the obvious conclusion that it is differential (Gear Oil) oil.

There's a procedure in Bentley in which the cv joint is not removed from the spindle/upright, but the entire upright and axle is removed from the car. The differential seal and the leaky o-ring can then be changed.

Thanks Upallnight,

I already went to the dealership and picked up the seals you recommended. The guy at the parts department also concurred with your diagnosis and said that he has seen this specific leak before and was not surprised. I am confused by the last part of your previous post (about how to fix it). My plan was just to pull the entire passenger axle, unbolt the upright and replace the seal. Is there a different way to do it?

That is the correct way to replace the o-ring and seal. Most people would pull the axle out of the spindle/upright and remove the axle, but if you leave the axle bolted to the spindle/upright you don't need to mess with the axle nut that holds the CV joint to the hub.

I thought the axle on the Passenger/rightside was long so it could go through the oil pan? Are you saying I can pull it with out removing it from the wheel hub?

Yes, you will have to remove the entire upright/spindle from the strut, but the axle can still be bolted to the hub. The procedure is outlined in Bentley for replacing the differential seal.

Hi guys,

I put the new seals in over the weekend and drove around and it appears my small leak is gone (fingers crossed). I also noticed that when I pulled the axle out I lost a lot more differential fluid. When I finished and removed the fill plug for the front differential a lot more fluid came out. I think that part of my problem was that the differential was over filled (from previous owner).

Thanks for the help.

Thanks for coming back and reporting on your results and fix. So you replaced the o-ring and differential seal, correct? Was the differential oil really smelly like the old Hypoid gear oil of the past?

Yes I replaced both the o-ring and the seal. Once I remove axle and the housing where the o-ring goes it was apparent that was my leak. As for the smell, once I had the axle out the smell was more apparent. I wouldn't say it stinks, but it is a different smell than motor oil.

Again, thanks for the help.