Need help finding the oil leak (picture heavy)

[Bmwe5320023.0]

Hmmmm I think there would still be traces along the engine. But I've cleaned it pretty good now so I will give it a test drive and put some more dye into the engine oil
























It's as clean as it gets with brake cleaner

[Bmwe5320023.0]

Good news and bad news lol
I located the leak, but it's really not clear where it's coming from...it's as if it's coming from the top bolt of the differential.
Also good news us that it's clearly engine oil, as I only put the dye into engine oil this time

[andrewwynn]

Does dif bolt to the lower oil pan and does that hole go though into the pan that could be the source and also plugged ?


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[Bmwe5320023.0]

I'm not sure, it does look like it might to through the oil pan at the top...but I've literally never heard of such a leak before. And also, it would not make any sense to build it that way...
I think I previously removed the differential, don't remember why lol, and I don't think the engine oil started pouring out as a result. Maybe engine oil doesn't rise high enough until you start driving.
I'm gonna try to find a video of differential removal and see if any oil leaks out of the top bolt..

[wpoll]

Originally Posted by Bmwe5320023.0

... Maybe engine oil doesn't rise high enough until you start driving. ...

Quite the reverse; the oil level in the sump is reduced when the engine is running. If you check the oil with the engine running, it often doesn't even show on the dip-stick.

[Bmwe5320023.0]

The hole does not go through oil pan. It has a stop.
Also I removed the diff bolt just in case, and it's not oily, it's clean.






The only possibility I can think of would be a cracked block right by the differential bolt.

[wpoll]

More likely to be a pan gasket failure right at the point?

[Bmwe5320023.0]

It doesn't look like it. I took pictures above the differential.
The gasket seems pretty dry

[wpoll]

Originally Posted by Bmwe5320023.0

It doesn't look like it. I took pictures above the differential.
The gasket seems pretty dry

To test the crack theory maybe clean the area down again and don't run the car but inspect the sump casting and crankcase with the UV lamp - the UV might expose the source (the crack?) with finer detail.

[EODguy]

This looks like a mold defect or cycled aluminum where it was T4 but heat/cold cycleshave turned it intoT6.(top)

Where did the aluminum flake (bottom) come from?

Hopefully is it's a small crack, but after cleaning you could probably get away with some sort of surface sealant J.B. Weld, etc in a thin layer as you're only using for leak stopping not for structural strength....

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