Hi, Does anyone out there really know the REAL science when it comes to the why`s and when`s in changing car oil ? It just seems to me that even this synthetic craze is a gimmick in addition to changing your car oil every 3, 000 miles. The dealer told me every 3,000 miles and I called Honda in California and was told every 5,000 miles and the car took synthetic oil. I don`t know that synthetic oil is any better than say 5W30. My car starts in winter and summer the same with no problem using either weight oil. I think it`s been a real money maker over many years for the car businesses ( a real bread and butter item for them) by hook winking the public. What really does science say about it ? Please help. I didn't find the right solution from the Internet. References:- https://www.bogleheads.org/forum/viewtopic.php?t=220320 [url=https://jobs.vidzzy.com/hire-motion-infographics-animation-company/]Motion Infographic Animation Company[/url] Thanks!