It take only about 20 minutes to check the EGR cooler for leakage.
Just remove the inlet from the cooler to the intake, and look into the cooler for damp gooey soot. if the cooler is ok, you'll just see dry soot.
The BMW inspection TSB:
https://static.nhtsa.gov/odi/rcl/201...8V755-1757.pdf
I lost coolant a couple times and didn't look at my cooler till after the intake had holes burned through it. BMW did repair everything at no cost.