Oil type bmw 2007 525i 2.5lt

That's about 100,000 miles, I never change oil type or grade unless the engine starts using more than one quart between oil changes. I don't know what oil you have been using, but put Mobil One Synthetic, 5W-30. My cousin uses same type and grade but Castrol, it's just habit, I say that good oil is good oil.