Mysterious oil leak...searched with no avail!

[ChadJr]

So I has me a 97 328iS, M52, 180k on the clock. When I first bought it, it didnt leak a drop of oil. That was a year ago and 10k miles ago. Now it leaves a puddle when I leave it parked for over an hour. I've gone through 4 VCGs, two oil caps, and 30 VCG nut seals trying to fix this problem.

I'm in the process of a refresh, and I have the car apart up to where you can see the front of the block. There was a ton of gunk on the front of the motor, and the oil tends to puddle along the top of the BMW beauty cover. On top of that, my fireproofing is soaked with oil, but only towards the front. The fan shroud also gets covered in oil, and so does the expansion tank. Only on the passenger side, only the front.

On top of replacing the VCG 4 times (I am 100% sure it is not the VCG), I tried cleaning the motor and then run it and look for the leak while it runs. Didnt find anything. Im at a complete loss as to what it could be. The OFH looks dry, but I think I'm gonna replace the seal anyway since the car is apart.

Does anyone have any idea what it could be? Anything I can look for? The whole car is getting a transformation and I'd really like a non-leaking engine to be a part of that

Thanks everyone

[Smigz]

is the block baked with oil on the front and fades to normal about half way back?

If yes consider your oil filter housing gasket as the source which is a common problem if anything other than a socket is used to remove the oil filter cap.

I did mine last month and it took an afternoon. You spend more time cleaning off sludge than turning wrenches.

[kaineb]

The items up front that can leak are the :

Valve Cover Gasket
Vanos Oil Line (crush washer at front of head)
Vanos Solenoid O-rings
Front Crank Seal
Oil Pan Gasket
Vanos Unit Seal (To Head)

[motion]

Try cleaning the engine and compartment and purchase some dye and leak detection light. to find leaks.
http://www.amazon.com/Uview-413010-Battery-Powered-Detection/dp/B000NBWCFC/ref=pd_sim_sbs_auto_1?tag=5336432695-20
http://www.ebay.com/itm/Tracer-Products-TP3090-Dye-Lite-Gasoline-Engine-Oil-Dye-6-1oz-Bottles-/230744226559?pt=Motors_Automotive_Tools&hash=item35b96d7aff&vxp=mtr

[ChadJr]

is the block baked with oil on the front and fades to normal about half way back?

If yes consider your oil filter housing gasket as the source which is a common problem if anything other than a socket is used to remove the oil filter cap.

I did mine last month and it took an afternoon. You spend more time cleaning off sludge than turning wrenches.

This wasn't the case, the block was pretty evenly coated in oil. However, I noticed the VANOS pressure line was wet. I believe there is a hairline type puncture that only spews when pressurized. This seems to make sense as the ofh area was caked as well as the front of the engine.

I replaced the line and the OFH gasket along with the 4 crush washers. I will update when i get it running again to tell if the leak is gone or not. Cross your fingers for me everyone!

[ChadJr]

A final follow up to this; it was for sure the vanos line. A good 200 mile drive and she's still clean. Thanks for all your help everyone

[sully42]

Try cleaning the engine and compartment and purchase some dye and leak detection light. to find leaks.
http://www.amazon.com/Uview-413010-Battery-Powered-Detection/dp/B000NBWCFC/ref=pd_sim_sbs_auto_1?tag=5336432695-20
http://www.ebay.com/itm/Tracer-Products-TP3090-Dye-Lite-Gasoline-Engine-Oil-Dye-6-1oz-Bottles-/230744226559?pt=Motors_Automotive_Tools&hash=item35b96d7aff&vxp=mtr (http://rover.ebay.com/rover/1/711-53200-19255-0/1?campid=5335818596&toolid=10001&mpre=http%3A%2F%2Fwww.ebay.com%2Fitm%2FTracer-Products-TP3090-Dye-Lite-Gasoline-Engine-Oil-Dye-6-1oz-Bottles-%2F230744226559%3Fpt%3DMotors_Automotive_Tools%26a mp%3Bhash%3Ditem35b96d7aff%26amp%3Bvxp%3Dmtr)

I have used one of these in the past. And think that I will be again, unfortunately sooner then I want.