quote:If he doesn't do at least one analysis though, he will never know for sure if he's chosen the right interval.
Originally posted by GROUCHO MARX: Er, I think the poster indicated he didn't want to spend money to have his used oil analyzed.
quote:And if your analysis gives high numbers what do they really mean and what can you do about it? I read a test once where Mobil tested their oil over a period of 6 years without a change. The irons went up over 600 and when the engine teardown was done, they were not able to find the source of the iron.
Originally posted by Spector: The correct interval (which by the way I don't believe anyone has defined what a proper change interval is)will change throughout the life of the engine based upon climate, driving conditions etc. So assuming that analysis is expensive compared to the cost of a do it youself oil change then a 3-5000 change interval will probably protect that engine for as long as he wants to keep it. There is a lot to be said for not doing analysis especially when the cost is compared to another oil change. Is the correct interval when the oil has lost its ability to protect the engine (ie: what does that mean (protect the engine) and what specific factors determine that) or is it at some point before the oil has lost effectiveness. Wear is inevitable, how much wear is the owner willing to accept?