My son's Honda 02 Civic has just completed 80k miles. He just did an oil change using GT1-Synthetic which is designed for use in older high mileage vehicles. I want to ARX it but should I wait for the next oil change and use a conventional/group 111 or is it ok to start with a maintenance dose now? Appreciate any advice on how to proceed with treatment. There's no obvious problems like sludge and the car is running ok.
