Bob;
I own a 1997 328i,,i have been using Mobil 1 SYN 0w-40 year round,,i live in central ohio,,it was suggested to me to use a heavier weight such as Mobil 1 15w-50 SYN. for summer months,,also it was suggested to use Shell Rotella T6 5w-40 or 15w40,,Mobil 1 has an ACE3 rating i believe,,Shell does not,,is any of the Rotella oils ok to use,,the engine has 147,000 miles ,,and uses around a quart every 3,700 miles..
I own a 1997 328i,,i have been using Mobil 1 SYN 0w-40 year round,,i live in central ohio,,it was suggested to me to use a heavier weight such as Mobil 1 15w-50 SYN. for summer months,,also it was suggested to use Shell Rotella T6 5w-40 or 15w40,,Mobil 1 has an ACE3 rating i believe,,Shell does not,,is any of the Rotella oils ok to use,,the engine has 147,000 miles ,,and uses around a quart every 3,700 miles..