can run it if its always had synthetic depends on mileage you will have to run engine cleaner in it then switch over its about same price so why run it .it also is a very high detergent oil may cause oil leaks its better oil in some way
Always use synthetic oils in BMW's.
synthetic oil
A BMW 325 takes about 6 or so quarts of synthetic 5w-30. Do not use conventional oil unless you hate your BMW. You must use synthetic.
use BMW Synthetic 5W-30 oil or Mobil 1 Synthetic 0w-40 oil
5w 30 synthetic oil
5 / 40 fully synthetic oil
The same as a BMW 330i -- approx 7 quarts / 6.5 liters of synthetic oil.
For BMW 323i. the company recommends to use only synthetic 5w30 or 5w40 !
You will need to use 5w30 synthetic oil in your BMW e90 320i. The brand name doesn't matter, just as long as it is 5w30 synthetic.
DUE TO MY RESEARCH, I FOUND OUT ALL BMW SHOULD USE: Genuine BMW High Performance Full Synthetic Motor Oil, 5W-30
Look inside your BMW manual. Usually I put 5W-30 synthetic.
I would use a 10/40 synthetic in winter and 20/50 synthetic in summer.