Originally posted by Big Jim: I just like keeping the engine clean. My experience is that longer oil change intervals are more likely to lead to sludged up engines. Perhaps it is a little old fashioned, but I remember tearing down too many engines that had huge amounts of sludge. Even today's engines with today's oils are not immune. Look at the problems that Toyota has been having. I believe in agressive maintenance.
Jim,
About eight years ago, when I was an Amsoil dealer*, I occasionally would personally convert someone's car from conventional engine oil to Amsoil. Unless it was a very low-mileage vehicle w/ between 10-15K** (and few were), my method went like this:
> Dump old oil and filter > Install cheapest generic spin-on filter that would fit the car and add one quart of cheapest Brand X oil available that met spec > Add 16 oz can Amsoil Engine Flush. > Fill remainder of crankcase with remaining Brand X oil. > Idle engine at 2500-3000 rpm for 30-60 minutes, depending on appearance/smell of original oil. > Shut down. Remove filler cap. Lose flush oil and filter. > Drain for as long as required to purge "99.99%" of flush oil and allow solvent residue to volatilize and escape -- normally, no more than an hour. > Fill Amsoil spin-on filter with oil, install. Fill crankcase with Amsoil synth ... then what you'd do from that point after any oil change.
Basically, it was the automotive equivalant of a Barium enema.
And suffice to say (because I'm getting long-winded), it worked very well in returning the engine and lubrication system to a state near-enough to pristine that the synthetic oil could take over from there and the driver could expect an initial drain-interval far in excess of 3K .. and, with the next change, expect to be able to extend the drain-interval to the limit of the engine's baseline, mechanical condition.
Drumbo
_________________________________________________________ * Although I haven't been in the synlube business for a number of years, I have run Amsoil synlubes front-to-back in all my vehicles over the past 15 years.
** And if it was a high-mileage vehicle with an uncertain maintenence history, Amsoil never came up in conversation with the owner
