Our heavy trucks run the Kleenoil filter system, essentially it is an extra by-pass oil filter, that filters down to 1 micron (as opposed to a normal filter 10 - 35 micron) and it's main claim to fame is removing moisture and condensation. They say that by changing the kleenoil cartridge at every regular oil change interval you can run the same oil and spin-on filter to 40-60,000 km. I asked about the additive package in the oil, they claim that most of the additives are depleted by the formation of acid in the oil, apparently by removing the moisture the acid doesn't form and therefore the additives stay intact. They make a car sized version as well. Has anyone had any experience with this system? Right now I am staying with the normal oil changes as the car is still in warranty (don't want to take any chances). Even so I wonder if this would be a good system to ""even if I'm only extending the oil changes out to the Mfg "light duty" oil change interval?? Apparently he has oil annalysis on his own cars oil at 40,000km and it shows as still being OK to use.