Sometimes cars are too smart for their own good though. At work we have a huge fleet of vans and the newer Chevy's have a change oil indicator that turns on when the computer thinks it needs changing based on various factors. Sometimes it comes on a day or two after you get the oil changed! It's a pain to reset the light/computer as well. One of those things where you have to do three things at once and hold your tongue just right to get the light to reset! lol.

Of course we had some people that weren't too bright and instead of following their scheduled maintanence based on mileage, they waited until the light would come on. A few guys messed up their engines running on low oil waiting for the light instead of taking it in on time.

On a side note, the company I work for did a research study with GM testing vehicles, extending the mileage between oil changes and then testing the oil. They found that due to better engine and oil technology, regular oil lasted longer with no significant breakdown. Instead of changing the oil at 3000 to 4000 miles, we now go 6500 miles on our Chevy vans and GM guarantiees the warranties. Unfortunately, the fleet manager has now changed over to Fords as they are much cheaper and Ford won't make the same guarantee that GM did. Oh well . . .