Synthetic Oil vs Regular Engine Oil
Synthetic oils have been around for quite some time and are man made. If we take a look at molecular level of synthetic we will see that the molecules have a uniform size and are smaller while on conventional oils they are bigger and different sizes.
This configuration will make Synthetic better at heat transfer and the engine will run cooler. Also the lubricating properties are amplified by small size molecules. Most of the damage on a car’s engine over a long period of time is done on a cold start and synthetic oils with their low temperature flowing capabilities will perform better.
There is one think though that regular oil excel: Price. Synthetic will cost at least 3-4 times more than conventional regular oil and while is better for your engine it might be hard on your pocket.While synthetic will not break up during normal car operation It will for sure get dirty and the oil filter has a limit. Engines will produce acids, soot, moisture and oil is needed to keep them suspended until filtered out or drained during oil change.
Oil filter will filter most of these pollutant but it can only take so much. By the time that the oil filter is overrun and cant filter anymore all these pollutant will accumulate vital parts of the engine causing varnish and sludge. At this point it does not matter anymore what kind of oil you have there.
Believing that synthetic oil can be used to obtain much longer oil changes intervals is wrong and dangerous for your engine. Oil companies stopped recommending 25.000 miles oil changes after lawsuits started pouring in from people with blown engines. Using the synthetic oil and changing it on reasonable intervals is the best but Expensive combination.
Another option is to change the oil at shorter intervals(over 3000 miles anyway) using quality conventional regular oil.It is cheaper for you and better for the engine. By the way, it has been proven repeatedly that cars will run for a very long time and a lot of miles on conventional oils when changed on proper intervals.
My car for example, a 1994 Es300 has 217.000 miles on the original engine. I changed the oil every 4000 miles using conventional and yet I never experienced an engine breakdown. So, in the long run if i had used synthetic it will have been cash down the drain, by this time my car holds no value anymore and a “super clean” engine will make no difference to me or the car.
Usually people can not keep their cars long enough (over 200.000 miles) to rip the benefits of an expensive synthetic oil and up to that mileage regular oil will do just fine. Especially if you are buying a used car that have been running all its life on conventional oil it does not make any sense to start pouring synthetic(money) in it, you will see absolutely no benefits.
Anyway, if you can afford it then by any means “go nuts”, put synthetic oil in there.