Hi.
I tried to do an oil change on my 1999.5 TDI on the weekend, but I couldn't remove the black plastic cap where the oil filter goes. It said 25N-M on it, but I assumed this was the tightening torque, as the arrow pointed clockwise. I had to take it to a VW dealer the next day, and he had no trouble getting it off. Luckily I had all the oil and the filter, so it was only an additional $14.50 for this to be done (he also checked my fluids, runnings lights, and greased my door hinges and lubricated my locks for me... not bad for $14.50 I guess). My theory is that after a day of driving around, the cap had expanded into the metal filter surround, essentially becoming stuck. Maybe when they changed it all the parts were cold, and free to move.
But to make it clear for next time, is there a trick to get it off?