which one should i use at temperatures,+20f to + 80f.(-7c. to +27c.) oil is 76 super synthetic blend, and my firebird v6 has 112500 miles on it.which one will be better and would provide better protection,5w30 or 10w30?
yes it does,5w30 preferred,but 10w30 can be used if its going to be 0f (-18c.)or above,says my owners manual.im just worried a bit over 5w30 that it shears down quicker than 10w30.and as far as i now,10w30 in summer should be better to use than 5w30,right?