I purchased a 2013 2-door JK with 91,000 a few months ago. It was basically stock and in excellent condition. I have been cleaning it up and replacing normal wear items. The previous owner swears he changed the oil and filter every 5,000 miles. The engine sounds great and I put Mobil 1 in shortly after I got it. I put about 1,000 miles on it and oil still looks fresh and is right up on the dipstick. I put new brakes all around, new shocks, new soft top and half doors and I have changed the oil cooler, spark plugs, PCV valve and all the fluids except the coolant hence my questions. I have 2 gallons of MOPAR OAT coolant which I was going to change along with a new thermostat, upper and lower radiator hose and serpentine belt. Considering the mileage, would it be a good idea to replace the belt tensioner, idler pulleys and water pump? I plan on driving the Jeep to Jamboree in Tennessee next May and do not want to have any surprises. Since this is my first Jeep, I don't know how long those parts are supposed to last.