Oil pans don't have a specific bolt sequence like a cylinder head or crankshaft bolts.
Use Silicone sealant D 176 404 A2
Removing
Remove center, left and right sound insulation trays:
Drain engine oil.
Remove securing bolts for oil pan.
Loosen oil pan with light blows of a rubber-headed hammer, if necessary.
Remove oil pan.
Remove sealant residue on cylinder block with a flat scraper.
Remove sealant residue on oil pan with a rotating brush, e.g. a drill motor with a plastic brush (wear eye protection).
Clean sealing surfaces. Surfaces must be free of oil and grease.
Installing
Note: Observe the use-by date of the sealing compound.
The oil pan must be installed within 5 minutes of applying the silicone sealing compound.
Cut off tube nozzle at forward marking (approx. nozzle diameter: 3 mm).
Apply silicone sealing compound, as shown, to clean oil pan sealing surface. Sealant bead must be 2 to 3 mm thick
Run along inner side of bolt holes
The sealing compound bead must not be thicker, otherwise excess sealing compound will enter the oil pan and may block the oil suction pipe strainer.
Apply silicone sealant bead carefully as shown to areas marked by arrows. (Illustration shows position of sealant bead on cylinder block).
Install oil pan immediately and tighten all oil pan bolts lightly.
The oil pan must be flush with the cylinder block.
Tighten oil pan bolts to 15 Nm.
Tighten oil pan/transmission bolts to 45 Nm.
Let the sealing compound dry for approx. 30 minutes after installing the oil pan. Only then fill the engine with oil.
Further assembly is basically the reverse of the disassembly procedure.