Reasons I ask are: 1) The owners manual does not have a weight recomendation, just a 10K interval. I think it does give a API grade, but no viscosity. 2) This car is a 98 Beetle with the 2.0 I4. It has had very infrequent oil changes (at least one 33K OCI that my GF will confess to) and I'm running the first of 2 ARX treatments now with 5w-30 dino. Does anyone know what the recommended viscosity for this engine is? I'm also thinking I should go one weight higher because of the massive amount of wear that has probably occured. What do you gusy think?