I have a 1999 and the air filter is all the way on the upper left hand side after you open the hood, remove the plastic and the big vacuum looking hose, you can see the housing for the air filter. It is a huge pain, clamps are really tight and you are better off just paying to get it done. It usually costs less than the air filter itself if you bought it yourself.
http://www.tobio.info/passat/howtos/passat_air_filter.HTML
http://www.tobio.info/passat/howtos/passat_air_filter.html This is for the 2.8L V6 30V
It's located near the oil filter and on oil cooler/filter plate.
inside air filter housing
http://www.tobio.info/passat/howtos/passat_air_filter.html
2004 VOLKSWAGEN PASSAT 2.8L 6-cyl Engine Code AHA, ATQCAPACITIESAWD with filter..........5.3 quartsFWD with filter..........6.4 quarts 2004 VOLKSWAGEN PASSAT 1.8L 4-cyl Engine Code AWM TurboCAPACITIESEngine, with filter..........4.2 quarts 2004 VOLKSWAGEN PASSAT 2.0L 4-cyl Engine Code 1968cc TurboDieselCAPACITIES2004 VOLKSWAGEN PASSAT 4.0L 8-cyl Engine Code BDPCAPACITIESEngine, with filter..........8.8 quarts Good Luck and Remember.Change Your Mind, Not Your Oil.Use the First In Synthetic Motor Oil's.See My Bio For Information & Contact Details.
behind the oil filter
The 1.8 L turbo capacity is 3.9 quarts with filter change. The 2.8 L 6 cylinder capacity is 6.6 quarts with filter change.
http://www.tobio.info/passat/howtos/passat_air_filter.html
locate the oil filter , most volkswagen have the "ops" on the filter hosing just above the filter.
I am looking for the same answer. I found Castrol Synthetic Oil meets the Volkswagen Passat requirements per the Passat manual. I found it at an Advance Auto Parts store. I havn't checked the drain plug location or type, or the filter location.
http://www.tobio.info/passat/howtos/passat_air_filter.html
http://www.tobio.info/passat/howtos/passat_air_filter.html