New oil getting dirty FAST!

[JT520i]

I purchased a '93 520i about 3 months ago, and since the oil was quite dirty, I changed it with the filter even thought the service indicator still showed plenty of time left (the previous owner had the vehicle regularly serviced at a local dealership). Now, 700 miles later, the oil is getting dirty much faster than I expected. Since I always change my oil religiously at or before 3000 miles, I decided to use dino oil. In this case, I used Castrol High milage 10W-40 as recommended in the owners manual for winter conditions.

Being new to BMW ownership, I guess my question is: Is this unusual for an older BMW? If it continues to degrade at this rate, I'm not sure I feel comfortable even letting it go to 3000 mi.

What would cause it to blacken so quickly? Detergents in the oil? Deposits in the engine? Any other causes?
Thanks, JT

[632 Regal]

most likely a real dirty engine with crud buildup, I would use the dino oil untill most of it cleans up.

[uscharalph]

I purchased a '93 520i about 3 months ago, and since the oil was quite dirty, I changed it with the filter even thought the service indicator still showed plenty of time left (the previous owner had the vehicle regularly serviced at a local dealership). Now, 700 miles later, the oil is getting dirty much faster than I expected. Since I always change my oil religiously at or before 3000 miles, I decided to use dino oil. In this case, I used Castrol High milage 10W-40 as recommended in the owners manual for winter conditions.

Being new to BMW ownership, I guess my question is: Is this unusual for an older BMW? If it continues to degrade at this rate, I'm not sure I feel comfortable even letting it go to 3000 mi.

What would cause it to blacken so quickly? Detergents in the oil? Deposits in the engine? Any other causes?
Thanks, JT

Just change at a accelerated interval for a couple of changes. It'l probably clean out.