120k mile engine looks brand new from using synthetic oil

ive pulled appart stuff with dino oil, changed regularly, and they have sludge.

^^^THIS.
I changed a valve cover gasket a few years ago on my mother in laws Tercel with 140+k miles and she claimed that she took it every 3k miles to get changed with Castrol Dino oil ever since she bought the car new in 1997. Father in law confirmed what she said. That engine looked like it had crude oil in it. Almost like wheel bearing grease. FTS.
 
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