Fully Synthetic Oil Can Last How Long?

Lower viscosity oil will improve fuel economy, regardless whether it is conventional mineral, hydro-cracked, PAO or Ester. But lower quality based would risk viscosity being sheared down below allowable limit in short time, probably shorter than pre-planned oil change interval. So synthetic base would be a more rational choice for low viscosity oil if you are looking at both longer drain interval and fuel economy. Apart from this, formulation, such as lubricity and fluidity in the oil would play a part in improving the fuel economy.

Bro. YSW,
Longtime no see and Happy CNY.....

Happy CNY to you and your family, too.

Too bad nowadays the forum are pretty slow, if not, will be good to have more of your expertise here......

Woah, don't say like that, I am still learning...

Well, I cannot argue with that as new technology always coming and learning never stops, but learning at what stage is the difference. You are at the top end, Master degree.....

yes. lower viscosity oil is the way to go (good quality ones). it is a common misconception that higher viscosity means better protection.

a high quality low viscosity can outperform a higher viscosity oil while giving better FC.

some oil stated able to do long interval. but you need to think about the oil filter condition. not all standard oil filter are able to get to that long extend "severe" factors also plays a role as a short trips, driving maximum loads, severe dust conditions, stop and go driving, excessive idling, hard driving, engine temp, and other conditions may affect the filter lifetime.

you may get a good premium oil that can extend to a wider mileage but your oil filter is not able to do that. you will get a not so good filtration and it will defeat the purpose

Extending oil change interval is just circulating the old oil over and over again. As far as I know most extended oil are sold mostly in US where trucks travel long distances day in and day out, and there the labor also is expensive.
Here we can consider the oil being cheap and especially cheap labor. I rather shorten my oil change interval....lol

i fully agree to this....

i wouldnt extend oil change interval too much no matter how long car manufacturer wrote in the service book.....


i've seen to many damage done on too many cars and i'm not jumping in to join the fun of "scheduled" engine replacement....




one fact: no matter how good the engine oil.....its still an oil.....unless one day car engine is equipped with canggih "oil refinery system" instead of the very basic oil filter...