Originally Posted by chii370

because synthetics dont naturally degrade do to heat stress thats "why bother" in a perfect machine with no flaws you can essentially use synthetic oil for the lifetime of the machine. My old job had machines that used full synth oil and didnt need to be changed for 15-20 years as long as the FILTER was always changed at the interval the oil companies have padlove trained all your dumb asses into believing it needs to be changed. of course they are going to tell you it needs changed every 6000 miles. WHO POCKETS FROM YOUR STUPIDITY. they would tell you that you need to change it every 2.5 seconds if they could get away with it without someone FINALLY raising a suspicious eyebrow lol. ****, i remember growing up it used to be every 10k miles, sometimes even 15. now its 6-7500. I have actually tested this. I ran royal purple in my subi for 4 years and just swapped out K&N filters "its a bi7ch" and after all that time the oil was still as clean as ever. although I also have a RE magnet drain plug but I would never find anything on it so it ether doesn't work or the oil is doing its job.

switching from conventional to synth doesn't matter. switching from synth to conventional does. and synth eating seals ...... thats long in the past, additives have since gotten so much better. just dont put that high mileage **** in, it has weird detergents and other crap in it to fight "engine buildup"

if you dont believe me, theres plenty of googling to be done. by all means second check.