I own a 2000 323 and I always use Mobil 1 this is a very good oil and recommended for this cars
--More to the point, Mobil 1 is considered a "5w" grade of synthetic motor oil, meaning its "winter" cold-start viscosity is 5 degrees Centigrade... Which is low. And that's a good thing. Plus it seems Mobil 1 comes with lots of extra "good for your engine" bonus ingredients. All of this suggests it's a good motor oi, for your 323.
5w 30 synthetic oil
The 1998 BMW 323 car can safely hold 7 quarts of motor oil. It is not recommended that more than 7 be used.
The type of oil for a 1997, BMW 540-I is a synthetic 5w40 blend.
In a 2000 BMW 323ci, it takes just under 7 quarts. If you use exactly 7 quarts, it will be a little much.
The short answer (for an M54 3.0) is a synthetic oil with an API specification of SH or later. Viscosity of 5W-30 or 5W-40.
Hash oil
Synthetic oil only
The type of oil used for a 1996 BMW 318i is 5W 40. This oil can be purchased at any auto parts store such as AutoZone or NAPA.
Castrol Full Synthetic 5w30 is what BMW recommends
Castrol Full Synthetic 5w30 is what BMW recommends.
10/40
10W30 oil is fine for that car. I also have a 1991 BMW 318i and my mechanic who worked for BMW for 20years says to as well.