I had a 1985 Nissan 300ZX that I put 315,000 miles on with factory recommended maintenance, i.e., 3000 mile oil changes. I finally let it go because it failed a state emission test after 25 years. I currently have a 2000 Toyota Camry V6 that has 318,000 miles and passed it's last emission test and is still going strong. My guess is that lubricants are much better and the metallurgy of engine components also has something to do with it.
