Pure synthetic oil, 15,000 miles all the way. At about 5,000-6,000 miles you might need to dump one or two quarts of oil in just so the engine keeps running, new engines usually burn oil the first few thousand miles. Your car will tell you, when you hit around that mile marker your car will start beeping excessively (it’s confusing), but just check the oil and that’s all it needs, the beeps will start and don’t stop you can turn off your car and it will keep beeping. BTW BMW recommends Castro Synthetic Oil!