Engine oil Mobil or Castrol

My VW dealer uses Castrol Syntec 5W-40 that meets the VW 502 standard.

I use castrol

When I bought my (new) 2002 Jetta, I did quite a bit of research on the various synthetic oils for turbo diesel engines. I came away the most impressed with Mobil Delvac-1 in the SILVER jug. The numbers that were available online seemed to suggest that this was one of the better choices. I've run Delvac-1 since my Jetta's first oil change. Not the cheapest synthetic out there, but I've been happy with what I've seen.

For some odd reason it seems that mobil 1 iron numbers are a bit higher in the 1.8T. I switched to Castrol Syntec 0w-30 and my iron numbers went down.

Same here 0W-40 since new, now have over 140K, runs like a dream.

Mine's had Mobile 1 since day 1. Up until 45K-ish it was 5w- or 10w-40(?) Anyway, I switched to 0w-40 and I know my milage is a tad better and I swear the seat of my pants tells me the engine has more... spunk.

0w-40 is a great oil for the VR6. It's not too thin. At operating temp, it's a 40-weight oil and viscosity-wise is no different than 5w-40 or 10w-40. It is thinner than these oils at start-up, which isn't a bad thing. I used 0w-40 for many miles without any issues and the engine is still in amazing shape at 211k+ miles. FYI, 0w-40 is used as factory fill in all Mercedes AMG engines. If it's not too thin for those beasts, then it's not too thin for a VR.

0-40W here all year round in Chicago 138k miles and still going strong

I just changed my oil and filter on my 2006 GLI 2.0T. I used Mobil 1 15w-50 and a MANN filter purchased from the VW Dealer. My best friend is an awesome Audi/VW tech and he advised me that was fine combo.

castrol 5w40 is what vw puts in the new passat. just did my 5k oil change the other day. i used a original vw oil filter also.