I had a Mustang GT that I switched over to synthetic when it had around 180,000 miles on it. No problems with it until I sold it with around 350,000 miles on it . I was going to run synthetic in my Dodge when I first got it but then I learned about it's love for oil lol. I couldn't afford to use synthetic! After I fixed the plenum it slowed down the oil use considerably but I haven't decided if I'm going to try synthetic again or not. I'm in Florida though so I really don't have to worry about the cold temps