just simple fast explanation :

- synthetic oil is good, it lubricates better bcoz its particles are smaller (than mineral oils), thus covering the engine parts more completely

-new car should use synthetic as the lubrication will be better

-old cars should not use synthetic oil. u gonna waste yr $. why? bcoz old cars, the engine parts are worn, synthetic oil, its particles being tinier will seep thru the worn out parts into the combustion chamber and be burnt or worse scenario leaked away.tat is why old car tat uses synthetic usually have to top up before the month ends