Hey gang i've been using Castrol Syntec 5w-40 synthetic since i got the car but i see a lot of people using 0w-40 and even 5w-30 which is best for a B5? I lost my manual so i'm not sure if the A4 B5 has to meet ACEA A3 or A5?

Thanks

 

These standards came out in 2002, after your car was made. Either A3 or A5 can be used.

 

i use M1 5W-30, works great

 

Castrol 5-40 is perfect.