Edit. I don’t have the nut. Thanks for the help.

 

Do you have the stock cap or a replacement Dorman cap as shown? The stock cap has ridges/flutes around it and they make a specific size cap wrench that fits those ridges or flutes.
I have one similar to this:

https://www.ecstuning.com/b-schwaben...8-drive/fc-04/

 

stock but it looks just like this one

 

They make a stock cap wrench that fits the flutes and works perfectly.

 

strange, I could have sworn the other day I had the nut and just looked and it’s the regular cap. I have a tool to remove this one.

 

You will have to look again, the 2016 depending on vin number has 2 different oil filters---which may mean 2 different caps? I just went out to the garage---I do not have a nut on top, just the flutes.

 

I just ordered a 27mm 5 flute socket from Motivxtools.com works great on my 2013 E550.