Believe it's a 14mm. could be a 9/16 too.
The original engine oil drain plug wrench size should be 15mm.
its 9/16's
Bottom of the engine on the oil pan.
on the oil pan
where is the oil drain plug on the bmw 316 year 1993 what size is plug?
Look at the rear or side of the oil pan
Lower Side or bottom of oil pan
Bottom of engine on the oil pan.
counter-clockwise
The oil pan is mounted on the bottom of the engine block. It is the pan with the drain plug. The drain plug you remove to drain the engine oil. Crawl under the truck and look around.
Below the oil pan. If you do not know you should not touch it.
On the bottom of the engine screwed into the oil pan.