To the OP

Have you had this car since new or not ?

I ask as many 2006 - 2008 V6 Passat's had engine issues caused by a defective bolt holding the oil pump in place - the bolt was ineffective and would back out, loosening the oil pump and cause untold damage to the engine. 3.6 L engines were affected also. Some engines went pop totally others didn't... was thinking maybe yours didn't but still had significant damage.

See link:

3.6 Oil Bolt Failure: Reference Material