If your oil pan is all wet with oil on your generation 1 Cooper or Cooper S you need to replace your oil pan gasket. We have been using Fel-Pro oil pan gaskets at the shop because we feel they are better than stock. It's designed the same as OEM, but the rubber section is a bit thicker and seals better once it's crushed in place. Fel-Pro is a trusted brand that has become a house hold name in the gasket market.
Note: Gasket is normally orange in color, but some times comes in blue and may not look like the photo.