what brand/weight oil?

I just purchased a 1995 325I, 80,000 miles. what is a good brand/weight oil to use for an oil change, and how often should I change it?

If the climate makes a difference, I live in southern California.

I just purchased a 1995 325I, 80,000 miles. what is a good brand/weight oil to use for an oil change, and how often should I change it?

oil should be changed every 3,000 miles or every 3 months, which ever comes first.
Not sure of the brand and weight, heavier oil in warm weather, lighter in freezing though.

I guess it all depends on if you believe the industry hype or the computer in your BMW. Your car will tell you when you should change your oil. It takes into the computation how much fuel you have used and the load the car has been under. Also the engine temperature,ambient air temperature, oil temperature, coolant temperature, number of starts including cold starts. The US Military quit going by mileage and had begun on oil testing for change intervals.They found out that almost all of the "industry standards had NO BEARING" on when you should change oil. Based on such testing, BMW has built a program into the car to monitor such data. If you drive in bumper to bumper traffic in a New York city cab, you would need to change oil more often than if you were to do all of your driving on the interstates. Probably by a factor of 3 to 4 while using conventional oils.

Oil brand & weight? BMW has done some tests on some E30 325's that used Mobil One products. They used these cars for the 50K EPA tests. They then gave the cars to Mobil to use as sales rep cars. At 2 MILLION miles, they took back the cars & dissembled the engines. In one car, they found 2 parts that did not meet new spec dimensions but were still in the serviceable dimensions. They reassembled the engines & put another 500K miles on them. They are now in the museum in Munich.

I have used Mobil 1 since my car was new. I started out on 15W-50 as I live in Phoenix, Az. Last change, I switched to 0W-40 which is designed for these engines. Better fuel mileage and actually better protection when compared to 15W-50 according to a retired GM engine engineer friend of mine. I have used nothing but Mobil 1 since 1979 and will not use anything else.