I have a 99 Ford Contour, 2.0L 4 cylinder DOHC with 116,551 miles on it at the time of sample. The oil has been in the car for about 3 or 4 months. I'm using AMSOIL SAE 5W-30 XL Synthetic Motor Oil. I use Group 7 oil filters which are made by purolator.
I do about 120 miles a day, almost all...