Found this. Looks like I messed up by removing the plug. 
Chevrolet's turbo-diesel four-cylinder was designed in Torino, Italy, and is manufactured in Kaiserslautern, Germany. It's not a new engine, as it is already being used in Opel Astras and various other GM vehicles around the world. Still, the U.S. version is unique, including the engine oil pan drain plug.
Engine Oil/Filter Capacity
Notice: DO NOT overfill the diesel engine when performing an engine oil/filter change. If the diesel engine is overfilled, the engine can continue to run when turned OFF by using the additional oil as fuel, resulting in internal engine and exhaust system damage.
When performing an engine oil/filter change, it is critical that the diesel engine is not overfilled. Including the oil filter, the engine oil capacity is 4.75 quarts (4.5 liters) of oil.
Engine Oil Pan Drain Plug:
Notice: DO NOT remove the engine oil pan drain plug when changing the engine oil. Removing the engine oil pan drain plug completely will result in the engine oil pan drain plug gasket becoming dislodged or lost.
The engine oil pan drain plug looks like a banjo bolt, but acts more like a valve. This type of drain plug does not have to be removed to drain the oil. Just unscrew it a few turns and the oil will flow out of the holes in the bolt.
Notice: DO NOT remove the engine oil pan drain plug when changing the engine oil.
Chevrolet's turbo-diesel four-cylinder was designed in Torino, Italy, and is manufactured in Kaiserslautern, Germany. It's not a new engine, as it is already being used in Opel Astras and various other GM vehicles around the world. Still, the U.S. version is unique, including the engine oil pan drain plug.
Engine Oil/Filter Capacity
Notice: DO NOT overfill the diesel engine when performing an engine oil/filter change. If the diesel engine is overfilled, the engine can continue to run when turned OFF by using the additional oil as fuel, resulting in internal engine and exhaust system damage.
When performing an engine oil/filter change, it is critical that the diesel engine is not overfilled. Including the oil filter, the engine oil capacity is 4.75 quarts (4.5 liters) of oil.
Engine Oil Pan Drain Plug:
Notice: DO NOT remove the engine oil pan drain plug when changing the engine oil. Removing the engine oil pan drain plug completely will result in the engine oil pan drain plug gasket becoming dislodged or lost.
The engine oil pan drain plug looks like a banjo bolt, but acts more like a valve. This type of drain plug does not have to be removed to drain the oil. Just unscrew it a few turns and the oil will flow out of the holes in the bolt.
Notice: DO NOT remove the engine oil pan drain plug when changing the engine oil.
