Originally Posted by Classic320i
First If there is high mileage on that engine, its nornal for engine to burn some oil up to 1 qt. every 700-1000 miles depending on condition of engine and how you push it in the higher rpms, otherwise if there no external leaks pull the spark plugs they will show sign of oil deposit.
not entirely true.
I go through a quarter to a half a quart every thousand miles. My plugs, when last changed(few thousand ago) showed no sign of oil deposits. they looked new, cept they were 130 thousand miles old.
No external leaks either.
the dealer told me its normal. as for mixing grades i dont think its recommended. But i think if its the same numbered oil, and synthetic like the other then you should be fine.
try to replace it with the same oil though.
Is it a 330?