Questions about 2001 VW Passat and synthetic oil

We have a 2001.5 1.8L Turbo VW Passat with 65K miles on it.

I think the dealer used synthetic oil this oil change for the first time.

Once you use synthetic oil, can you switch back to regular? If not
recommended, what happens if you do it anyway? (Just wondering)

I understand the 2001.5 VW Passat came with regular oil but can use
synthetic. Is it better to use synthetic? Why? How much better?

Normally, VW changes our oil every 5K miles. Is it the same schedule with
synthetic?

Can a mechanic tell what type of oil is in the car?

I needed to add some oil two months ago and called the dealer to find what
kind I should add. He told me, since it was a 2001 turbo that it takes
synthetic oil so I added about half a pint of synthetic. Now I'm thinking
I had regular oil in there. Any problems mixing a little synthetic with
non?

Thanks very much!

Joy

They mix just fine!
Ben

Joy wrote:
> We have a 2001.5 1.8L Turbo VW Passat with 65K miles on it.
>
> I think the dealer used synthetic oil this oil change for the first time.
>
> Once you use synthetic oil, can you switch back to regular? If not
> recommended, what happens if you do it anyway? (Just wondering)
>
> I understand the 2001.5 VW Passat came with regular oil but can use
> synthetic. Is it better to use synthetic? Why? How much better?
>
> Normally, VW changes our oil every 5K miles. Is it the same schedule with
> synthetic?
>
> Can a mechanic tell what type of oil is in the car?
>
> I needed to add some oil two months ago and called the dealer to find what
> kind I should add. He told me, since it was a 2001 turbo that it takes
> synthetic oil so I added about half a pint of synthetic. Now I'm thinking
> I had regular oil in there. Any problems mixing a little synthetic with
> non?
>
> Thanks very much!
>
> Joy