I know there are tons of oil genius' out there so I am going to ask for some advice. I have an 87 Jeep Wrangler with only 37K miles, still on the original motor that is drivin Very low miles each year. It probably gets like 4K miles a year. What kinda oil should I go for? Thinkin synthetic right? and then would I be able to change the oil like only once a year?