Many years ago my father told me that if your car or truck seems to use more oil then you would like try going up a grade. However he was never specific on how much oil your car should or should not use to make the switch? I did take his advice on my 1992 Volvo 960 and went from Mobil 1 10w30 to Mobil 1 15-50 and my car never ran better and also then used little oil but that was also more then going up one grade. Is this advice still relevant with today's cars? I'm not saying going to 15-50 but say from a 5w20 to a 5w30 weight oil will it help reduce oil consumption if your car seems to use a fair amount of 5w20?