Q: 2012 Jaguar XJ 5 liter non supercharged engine oil and battery

Hi there. When you replace the battery, it is best to put a battery saver tool in the cigarette lighter to keep the computer memory. If you do not have a battery saver, then the computer will loose its memory and it will take 10 starts or 4 days to relearn a complete cycle. For the engine oil, Castrol oil is designed to go up to 3,000 miles or 3 months of driving. High mileage Castrol oil is designed to go to 5,500 miles or 5 months. Semi-Synthetic Castrol oil is designed to go up to 5,500 miles or 5 months. Full synthetic Castrol oil is designed to go to 7,500 miles or 7 months. The time or miles is determined on normal engine combustion and normal driving conditions. Hard driving or poor fuel mileage driving will decrease the time and mileage to the Castrol oil life. If you need further assistance with the engine oil and battery, then seek out a professional, such as one from Your Mechanic, to help you.