u/Spiritual-Bag-8412

I had my q50 turbos replaced a week ago by my dealership. I’m starting to notice some spots underneath my car, it’s not a thick and greasy liquid. It dries fast but the spot doesn’t go away and when I use a wet wipe the colour appears to be black. I called my dealership and explained this to them and they said that the technicians have to spray the parts when doing the installation and that it may just be residue. I want to know if this is normal? Can someone who has replaced there turbos let me know if they have experienced this?