Engine life is determined by frequent oil changes and stopping a car almost immediately if overheats. Any engine driven with infrequent oil changes, driven with low oil level, or overheated harms an engine and reduces its life. I would expect 250,000 miles if the oil is changed e very 3000 miles.
You should get 250,000 if the oil is changed every 15,000 mile WITH synthetic oil like it is suppose to be. My brother has an 4.4 X5 with 198,00 on it and my 540I sport has 185,000
If you are questioning it remove the oil filler cap and look inside for any sludge indicating lack of oil changes or conventional oil changes,.... stay away if there is any sludge at all!!!!!!!!!!!