I have a 2009 Subaru Impreza that has 10100 miles on it right now. I switched to valvoline synpower at 7k miles. I took my car to have a noise looked at, and the dealer took it upon themselves to rotate the tires and do the oil. I never even asked for this! Then they try to charge me for it. I made a big fuss and it was waived. Question: Should I leave this oil in my car or drain it right away? It's valvoline conventional oil. My car has only been through 1 synthetic oil change. The previous oil was a factory fill and the first oil change at the dealer.