greggoryh
+1y
I was always led to believe that you use regular oil for break in purposes, then after break in, you can run synthetic in any engine. As for synthetic being thinner, not true. If you are running 10W30 conventional, and you switch to 10W30 synthetic, then only real difference is that synthetic flows better, giving the illusion of being thinner, but it's still 10W30. This is why it's labelled by weight. I know where you're coming from in the seal dept. tho. If you've ran conventional for 120000km, it's best to switch to a high mileage oil instead of a synthetic. Reason being, high mileage oils have special additives that condition the seals, keeping them better as you rack up the KM's, whereas the synthetic has more additives to keep the engine cleaner. These additives will remove the years of sludge and debris left by your old oil, thus exposing the inperfections in the seals that were plugged by the reminence of the old oil.
That's just my 2 cents on the topic. Please, don't crucify me if my views conflict with others
G