Dude, I havent changed the oil on my 2005 Dodge Grand Caravan for 3 years now. I just keep adding new oil to old oil and change the oil filter once a year. By the way, I started, on a whim, to fill up with that V-power gas from Shell. After about 2 tanks full, you can not feel the engine vibrating in the car compared to regular gas. This stuff  really works.