Hi,

Mineral oil was used on my vehicle last time instead of syntehtic. Will that harm my harm my engine. I realized it only after 8k kms

Modern 16v engines use semi-synthetic oils to give added protection and allow longer intervals between service. Mineral based oils lose their lubricosity over time and after 9000 miles will be less effective whereas modern semi-synthetic oil is less prone to this. The latter is also better at neutralising the products of combustion.

I'm not qualified to say whether this will/will not harm your engine, I don't know what effect the use of mineral oil would have over one service interval.

Its the oil specification that's important, not what its made from. If it met the required spec for your engine then there would be not problem. What oil was used (brand? viscosity?)

Is your car petrol or diesel? If it's petrol it won't have caused any problem. If you have the PD engine diesel, then change to fully synthetic oil of the correct viscosity and VW spec immediately. The diesels don't like mineral oil one little bit. It exposes the camshafts to excessive wear. However, I doubt it will have caused any problem in a diesel over 8k kms.