Gentlemen - I have a dilemma - I change the oil in MB eklasse 300 td. So far there was Elf 5w40 or full synthetic. Now it will be 10w40 because the car already has its km and if I flooded the synthetic, it will pass a year faster than kilometers to change so that the oil will still be fresh....... And now what to pour mobil 1 S or castrol magnatec? mobil, I haven't heard anything bad - about castrol, that it has become trash .... But again, this is how they advertise this magnetic oil ... and I don't know ..... Write how you have any experience with magnatec or mobile..... which is better ....