I have a large stash of 5-10w 30 chevron oils that I used on a couple beater cars. The cars have some oil consumption issue nothing major. whats the beat way to thicken up my oil selection? should I add a quart of 20w 50 on the oil change or add some maxlife oil additive? I'm thinking one of those 2 options....Thanks for any input. BTW the 3 beaters calls for 5 and 10w 30