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Discussion Starter #1
Ok, so after getting bearing job and SMG maintenance finished, I finally got the car on the ground and got it started and up to temperature while monitoring coolant temperature. Everything looks good in terms of coolant and oil temperature under high load and at idle. However, during the middle of a strong pull, I lost power.. no message or anything like reduced power, it just lost it's torque in the mid to high rpm range. Also, I had a suspicion that I was leaking oil before I had done the bearing job and thought maybe my oil level sensor was faulty (looks like it probably wasn't). I decided to put dye in the oil because I could'n't clearly see where oil was leaking from before doing the bearing job. There must be a hose leaking at the intake plenum on bank 1 based on the spattering pattern, but I'm not entirely sure. Bank 2 looks perfectly clean with no trace of oil.

I'd also like to mention that when the car was running at idle on the lift with underbody shields off, there was no visible leaking from the bottom of the vehicle. Also no leak visible from sitting without running.

I'll post my ISTA pictures here and post the oil leak pictures in a separate post since they're on my phone. Ignore the light module, damper control, SMG CAN faults. I ran the vehicles without lights installed, I have aftermarket coilovers and haven't coded out the error, and I believe the SMG fault is probably just due to battery voltage. Steering angle sensor may need to be cleaned/replaced (I've cleaned once and fixed the fault), but I think that could also be voltage related as well.

I appreciate all of our S85 whisperers on this forum ?.

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Discussion Starter #2
And here are the pictures at the passenger side of vehicle (bank 1 side). There's a little puddle of oil sitting on top of the hose in the first picture if you lift up the wiring harness going to the ebox.

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Looks like its from that PCV valve or oil hose that goes into the plenum. I have a similar thing but only the hose is wet looking and doesn’t leak as bad as yours. Its a common thing apparently, perhaps not this badly tho
 

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@Dmitry91 I do know for certain that the retaining ring on one of those hoses is kind of half broken. I'm not sure how high the pressure gets inside those hoses, but I guess if it's high enough it could easily push the hose off either the PCV valve or the valve cover, depending on which hose it is. and I guess that could probably cause an issue with the exhaust camshaft position sensor.
 

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I would also check the high pressure Oil line fitting on the bank 1 Vanos. If the line or one of the crush washers failed it could have sprayed oil over the passenger side of the engine, especially at speed or with the radiator fan on. That could also help explain the lose of power at mid/high RPM. Good luck and let us know what you find!
 

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Discussion Starter #6
Looks like it was definitely the vent hose that connects at the valve cover.. Retaining ring completely broken off.

(I removed O ring)
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