Noticed a LOT more leakage under my truck after getting an oil change at jiffy lube. At first I thought the PO May have been using something other than the conventional oil I got. Pulled out the dipstick and noticed I am way over the full line. How much extra is ok? A mm or two? Should I just dump it and start fresh, or let it leak to a reasonable level? Are these dipsticks on 60 series even accurate?