Okay can someone tell what is the filter like thing under the car.i Bought 2003 Audi A3 s line 2.0tdi. I went to change the oil so I jacked the car up took out the nut for the oil let it drained out. While I was under the car I seen a oil filter look alike so I opened it up thinking it was the oil filter and lots of oil came out but I then realised the oil filter was on top of the Engine . Long story short can someone tell me what I just opened under the car it had a filter in it but I didn't know what one. The anto shop just gave me one oil filter so I used it for the oil filter on top of the Engine. Thanks