Synthetic is okay in the HHR where I mentioned the screens, it's the high-mileage oil that has some additives in it that block those little screens. I change the oil on all my vehicles and use synthetic in them. I can buy high quality filters and Mobil 1 for less than anyone around me can give me a basic oil change (it might cost me the price of the filter over the cost of WM's basic service).
I want to ask you a question about oil changes. The computer on my Chevy Spark dwindles down oil life remaining too fast in my opinion. When it is down to 0% oil life left according to the car’s computer, I look at the oil dipstick and the oil looks clear and without any carbon and without any burnt oil smell. That was my method in the old days before we had computers telling us when to change the oil. Now that my 3 year-36K miles warranty is expired, my question is, am I doing the wrong thing by postponing oil change?