By now you would think there would be enough research , real life examinations , etc. to determine best readily available 5W30 synthetic oils to combat intake valve deposits which are still an issue with GDI engines . My Hyundai 2017 2.4L (non - turbo) GDI engine recommends 5W20 on the oil cap (absolutely because of CAFE) and now recommends 5W30 for this engine . I bounce between : M1 5W30 EP , Valvoline Advanced & EP 5W30 and even GSUD all in 5W30 5W30 all from my past SN+ , GF5 , D1 / Gen 2 synthetic oil stash running each no more than a 5K mile / 6 month OCI . What (if anything) do newer GF6 / SP D1 / Gen 3 synthetic 5W30 oils address with respect to GDI engines ?