This is just slightly off the subject (but, still relevant). When I listed my '97 5.4 F250 LD for sale, I was VERY miffed when a potential buyer refused the truck after pulling the dipstick and noting the 'dirty' oil and accusing me of poor maintenance. When I countered that I had records of regular oil/filter changes with synthetic, he was not convinced...then I demonstrated my inventory of oil and filters...then I poured out a quart of new oil into a measuring cup and pointed out to this idiot the VERY DARK appearance of some oil formulations. He left in a huff...good riddance!

Check it out...many syns are extremely dark out of the container. The color of oil on the dipstick is no longer a reliable check. Only an oil analysis will tell the true story.

 

It's still rather easy to tell when it's time for an oil change. It's not just the color of the oil, it's the texture and viscosity. Rub a drop of new synthetic between your fingers, then do the same with a drop of well used synthetic. You can definately tell a difference.