They went over the entire car.
Valve cover gasket was leaking. They also found and repaired leaks in the steering pinion seal and the rear axle seal.
Thank god for the CPO warranty, only cost me 50 bucks.
2005 330i ZHP (SOLD!) / 2006 X3 (SOLD!) / 2007 328xi (SOLD!) / 2011 328xi (SOLD!) / 2013 328xi