With how crucial and reliant engines are on proper oiling, I will never understand why people would risk internal engine failures by using unknown quality/brands of oil... but mostly don't understand people subscribing to these CAFE endorsed Looong oil change intervals????? I have never seen ONE engine destroyed from good maintenance, but have seen countless due to lack of proper maintenance intervals. People will risk losing thousandS of dollars to not spend 50 bucks on some good oil at a good interval.
Oil change interval is highly dependent on use and quality. If you use a high quality synthetic oil and are highway driving 6-7,000 miles no problem. If you’re tracking the car I’d change it every outing and if you drive it hard on the street regularly 3-4,000 miles depending. Any more than that you’re just spending money with no real mechanical benefit.
Oil being the lifeblood of the engine, I see no benefit in going as long as you can, or extended intervals. Most people don't know the damnedest thing about engines and will just follow a regiment that they've been told and sounds right to them. Some vehicles with good ring seal, ventilation would be perfectly fine going 5k highway miles before changing. Others would benefit from less (3k). I have a 2.4L Accord in the family that likes to drink oil. It has done so from day one. It eats one quart every 1000 miles and the oil gets darkened within 2k miles. If I went 7k highway miles on that vehicle it would have pitch black oil and be out of at least 3 quarts of its 4.4 qt capacity. Camry, same year, eats only a few drops. It would do 5k miles just fine. It doesn't start to darken until about 4k miles. In a scenario where most people are unaware of their own vehicles, neither vehicle would be negatively affected by frequent oil changes, whereas the Accord would suffer going longer. I also believe it's a waste of money to put clean fresh oil (with fresh additives package) into an oiling system that is dirty. Frequent oil changes keeps the oiling system reasonably clean... And that's never throwing money away. I'd rather spend fifty bucks here and there than ten grand all at once because I thought the oil was still good. And the only way to know you don't have too much fuel dilution too many times is sending samples to a lab. Nobody does that. Just change it at a proper frequency.
