At the bottom of the engine block.
I just got quoted $1,189 to replace the oil pan gasket on my 2006 BMW 525xi...
The oil filter on a 2001 BMW 525i is changed by placing a drain pan under the engine and slipping a filter wrench around the filter. It can then be loosened, removed, and a new filter put in its place.
Drain the oil from your oil pan. Remove the oil pan bolts. There are 24 oil pan bolts. The oil pan will come off.
Bolted into the bottom of the oil pan.
Under the car.
The oil pan is bolted to the bottom of the engine
climb under it an on the oil pan it has a screw an that's how you take change the oil in a 1997 BMW 313i
Bottom of the engine on the oil pan.
On the bottom of the oil pan - under the engine.
Carefully.
Under the engine at the bottom of the oil pan. The oil pan is the square looking thing that is the lowest part of the engine if you are under the car.
replace pan (junk yard, used part) or find a somone who welds aluminum. New oil pan from the dealer would be expencive.