latitude39

N52 3.0, 131k miles, build date: March 2006

Front differential is fully-coated with oil and grime.

Any ideas?

I do have a leaky valve cover gasket. The front of the engine, where the VANOS solenoids are, is coated with oil. However, I don't see oil leaking from the VCG on the left side of the engine above the differential.

Could it be a leaky Oil Separator?? I have removed the air filter so I could get a look at it but the Oil Separator is well hidden up above the starter. I don't see an oily mess on top of the starter.

The oil separator appears to be located directly above the differential.

Last month I replaced the differential's axle seal. I had noted that the base of the axle was oily and had attracted dust. In the past, this meant, to me, a torn radial seal. So I replaced it. The differential is more oily than ever.

The first two photos were taken before Christmas. The last photo was taken yesterday, almost 4 months later. You can see the problem is getting worse.

Please let me know what you think. I've collected a list of parts needed for the Oil Separator project but don't want to buy just yet. I need to be more sure of what is happening before spending $$.

latitude39

Any ideas are welcome.

pcy

It's difficult to pinpoint the source of the oil leak with all that dirt and oil residue. If I were you, I'd cleanup up the entire area with brake parts cleaner and check after few days of driving.

latitude39

Thanks pcy. I'll clean it off tonight and drive it a few days and reevaluate.

BTW, I've found your photos of the underside of the intake manifold (in the "Starter R&R" thread) to be very useful. Thank for that too.

pcy

Go thru each one of these and eliminate one by one...
valve cover gasket leak
oil filter CAP gasket (large o-ring) leak
oil filter HOUSING gasket leak,
lower oil pan
Due to gravity and wind force, leaks from any of those gaskets will migrate towards the bottom and on to the front diff.

If you are not able to find the source of the leak with a flash light, then take the car to an independent mechanic, they can add dye to the oil and the source of the leak can be traced much easier.

latitude39

Thanks for you inputs, pcy. I saw that you replaced CCV as PM, as I have done on my E46. I became inspired to do the same level of PM to my E60.

I am preparing to replace the CCV, VCG, both gaskets on the OFH, reman'd starter. I have all the gaskets and aluminum VCG bolts. I'm reviewing Bentley and TIS. There are conflicts in torque specifications, such as for the 3 bolts on the Valvetronic motor, which is an M6 bolt and is either 10 Nm or 4 Nm. I think that has to do with differences in cylinder head cover material (magAl or plastic) -- aluminum bolts for magAl and steel for plastic??? I don't know but the Valvetronic bolts I ordered, according to RealOEM, are definitely steel.

In short, I'm jumping ahead without determining precisely where the leak is coming from. It will be more clear without the intake manifold blocking my view. Wish me luck. The oil pan gasket seems to be sealed tight as a drum so I'm expecting to find leaks from above, and forward as you have mentioned.

pcy

When you are disconnecting various wires, label them with tape. That way you know where those wires were supposed to be connected. When you have 10 wires in your hand that look very similar, it's easy to make a mistake and connect them at wrong place.

When you are disconnecting the intake manifold and oil separator hoses, you will see what I am talking about.

latitude39

Thanks for the heads-up. I think I know what you're talking about--the heater wires for the CCV pipes and valve, right? I saw in another thread where you had shown someone how to reconnect those wires.

Yes, I will label, take photos, and work slowly and methodically since I do jobs like this once a year or so.

Here's a photo of the 3 heater wires I can account for, 1 for the valve and 2 for the insulated pipes.

latitude39

Here are my parts. I'll clean the oil as I go and look for the source(s) of the leaks.

My starter has been a little slow to react to the button push. Good time to replace it.

I wonder if there's anything else I could replace as PM while I've got the "lid" off.

latitude39

N52 3 liter
I like to collect torque specifications *before* starting work.

For the starter, my findings are:

Bentley and TIS disagree. TIS seems more believable so I'm using the TIS specification.

There are 2 M10 aluminum bolts that fasten the starter, one is 30mm long, the other 85mm.

Bentley says: 20 Nm + 180 degrees for both.

TIS says: 20Nm + 180 for the M10x85
TIS says: 20Nm + 90 for the M10x30

I'm going to use TIS. I think the short bolt might SNAP before getting to 180.

I wonder if later versions of the Bentley E60 manual have fixed this (refer to p. 121-17 in Bentley)