Originally posted by Protherius
@Sep 19 2004, 07:58 PM
A older friend of mine is a salesman has over 350,000 miles on his volvo (Never been in the shop for a major repair), so i asked him about oil changes and such. He told me changing your oil any earlier than every 10,000 miles is a complete rip-off. Granted using really good oil is essential but changing it so often is not. He told me one of his co-workers has 275,000 on his accord and has never changed his oil, only the filter. So I dont know why you would need an oil change in 1,000 miles
Have you seen the actual car? While many enthusiasts go overboard with oil changes, I can safely say that 275K miles is a lot much. The only way that this car could still be running is if it used quite a bit of oil since new and has required a good amount of top-up oil on a regular basis. The new oil would replenish the additives in the exisiting oil and keep it in servicable condition. Having said that I'm sure that there would be an awe inspiring amount of sludge in that motor and if it indeed still runs, it can't be very well.
The oil change interval that you should is highly dependant on the car you drive and how you drive it. Some engines are just harder on the oil than others. Due in part to the presence of VII's (viscocity index improvers) almost all oils will shear down with use. A byproduct of this is the formation of sludge. Some engines will go 10K miles before it is a problem, some will go as little 2K miles. If an engine has a poor ring seal, many of the acidic combustion byproducts will make their way into the oil. Oils contain additives to neutralize these acids, but there is only so much to go around. Once they are depleted, the oil becomes increasingly acidic and attacks various parts of the engine.
Driving style also has a huge influence. If you are always at high rpms and WOT you will have more shear and fuel dilution. This thins out the oil and will lead to increased wear. If you only drive short trip this will also increase fuel dilution. If you live in a cold climate it's also tougher on your engine and it's oil.
In short the only way of knowing for sure is to perform a UOA (used oil analysis). This will tell you if your oil change interval is right for your engine/driving conditions/driving style. It may be 10K miles, or even longer with some oils, or it may be dramatically shorter. Regardless, as long as the car is under warranty you should change the oil at least every 7500 miles. If you don't and you experience as engine problem you could be denied coverage.
Oh, if you run your oil too long a couple of times, you car will not blow up. A little more wear will occur but it won't be the end of the world. Just be sure to stay on top of it to give your car the best possible chance to provide you with long and reliable service.