Engine oil Castrol or OEM Mazda

For my 1.6 diesel I use Castrol Magnatec 0W30 Stop-Start C2 which was recommended to me by cox motor parts (great store for Honda parts)

It doesn't really matter as long as you get one that meets the specifications for your car which should be VW502 in your case. Mobil 1 0w40 and Castrol 5w40 both support that and are widely available for a reasonable price.

I’ve been using Castrol’s 5w-30 with the RN0720 spec (for DPF filtered diesels like yours and mine), it’s the best oil for thins engine. 100.000km doing oil changes every 10k and it’s as good as new, very good fuel economy and no leaks

Walmart sells the Castrol full synthetic eurocar recommended by Audi.

Just to let everyone know, VW/Audi recently dumped Castrol and they now roll with Mobil 1.

I run Castrol Edge in mine, the spec exceeds API SN PLUS/SP and ILSAC GF-6, coupled with a genuine hyundai filter

I use Castrol as it’s the OEM product and is cheap if you buy direct from Ford.

My more modern VW runs Castrol EDGE OE 5W-40 full synthetic. That's what my VW dealer in Utah fills cars with.

I ran Castrol 5W30 full synthetic in the engine.It burned a quart every 3500-4000.

I noticed when the castrol 508 spec wears. It smells Faintly of onions and beans. Strange smell indeed, when I took my car to street side VW out of Amarillo, Texas.