2012 mini cooper S (N18)

I was experiencing lean fuel warnings, bad LTFT, and found a leaky pcv when running a smoke test. Changed the membrane but no introverted , so i replaced the whole valve cover with a brand new OE cover.
everything seemed great, ran the engine for 20 to 30 miles, preformance seemed improved, fuel trims were great then this happened and the engine light came on...




I got home, waited for it to cool, removed the coils and spark plugs and found fresh oil on spark plug 1 and its thread. This has never been an issue on this car previously. Oil was not present in the spark plug well, this oil was deposited on the plug while inside the cylinder i guess.



The other spark plugs had evidence of some oil burning, but not wet, fresh oil like this one.

I smoke tested the engine by inserting the smoke tester into the oil filler hole (with no spark plugs installed)... smoke escaped from spark plug port1.

Thinking this was an issue with the valve cover i removed, checked everything over and fitted it again.

Did another smoke test and smoke is still escaping from port1 (no spark plugs fitted). now i read this could be normal, depending on the position of the engine.

I've cleared the codes but haven't started the engine and i don't know what to do..... because I don't think I've fixed whatever problem caused the codes in the first place.

Hopefully the experts here can give me some pointers...
Any ideas??

 

By the way when I took the new valve cover off I didn't see evidence of any oil leak at port1 (see yellow ring in photo), or at any port. I did see some crud where the red circle is and cleaned that off before taking this photo.... everything else in the photo was not touched, this is how i found it.

 

There should be a rubber seal on the valve cover around each spark plug hole. You definitely checked that that's in place on #1 and not damaged, right?

That doesn't look like oil on #1, it looks more like gasoline? Which could be the case if #1 was misfiring. In that case I'd also check the coil packs; make sure #1 isn't cracked, is properly tightened down, and that the wiring connection is good. You can also try swapping it to another cylinder to see if the issue follows the coil pack or not.

 

Could be either spark plug 1 and/or coil 1. Swaps tests with another cylinder is the smart way to go.

 

Interesting responses, thanks for your input. It fight occur to me that it might be petrol not oil, but it makes sense.

Yes i checked over the seals carefully before each install and I'm as sure as i can be that they were in place both first and second time (the photo shows no oil leaking past it the first time - port 1 in the yellow circle).

I have spare plugs and coils because i was planning to change them anyway. .. rather than just seal those old ones around, do you think it's worth just chucking the new ones into port1 to see what happens?

 

I would say that the current non-cylinder 1 plugs and coils are "known good". New parts can be bad right out of the box. Just my 2 cents.

 

Fair point..... I'll switch the existing ones around first then.

 

So, in the end I just decided to put new spark plugs and coils in as I had a new set of both, and the car seems to be running sweet. Nice and smooth smooth idle, no error codes and fuel trims look good. Only done a gentle 5 mile run so far but i think it's promising.