I bought brand new Fortuner GR-S my mileage on odo is 4100km. I want to choose best Synthetic oil for my Fortuner. I'm considering Amsoil Signature Diesel Max Duty 5W-30 it meets all the recommendations but its not available at the moment. Can I go with Shell Ultra 5W-30 as it covers both gasoline & diesel engine? Mobil Delvac 1 is expensive and both liqui moli's models aren't compatible with my Fortuner engine and guess what Toyota dealers are giving pathetic oil some of their representatives told me to pour 15w-40 or if I want Synthetic then they show me 0W-20 I mean what the heck they don't even read their own vehicles manual hahahah. Need your recommendations as i need to change it ASAP.