the car only gets occasional warm-up during winter months(2 start ups everyday day, move off drive way and back. plus a short drive ~20km round trip every week), then it's put in everyday use for 3 months in the summer time(everyday drive about 100km daily). Car's in sunny so-cal. What's a good oil to use if I must go with 1 year OCIs? Mobil 1 0w-40 or GC? Amsoil? MB factory recommands 5w40 I belive. thanks