What is the difference between synthetic and regular motor oil?

Synthetic has changed in recent years. A little history first....

In the days non synthetic oils were group 1 and group 2 base stocks. These are crude oils and polyphenins. Synthetic was as it was stated group 4 and group 5 base stocks which are PAO and POA esters (man made extreme quality esters which mimic esters once used from whale fat).

Then came the big Mobil 1 vs Castrol lawsuit. Mobil 1 contended that Castrol was using false advertising. Castrol had changed there formulation on there Full Synthetic oil. It NO longer was made from group 4 synthetic base stocks but was indeed made from group 3 base stock which is a conventional crude base stock, then severely hydro cracked and refined. group 3 is much higher quality than group 2 oils. Well it made it all the way to the supreme court were they ruled that oils made with group 3 base stocks are indeed synthetic because of the extreme amount of refinement, it isn't anything naturally occurring anymore. So Castrol was allowed to continue marketing the oil as fully synthetic. After this lawsuit a precedence was set for the definition of synthetic oil, one by one manufacturers started reformulating their synthetic motor oils from group 4's to group 3's , since group 3 is much cheaper to use.

This brings us to today most so called synthetics are just dino oil (conventional). Dont get me wrong the group 3 is far superior to group 2 it has much better flow characteristics in the cold and better resistance to heat. But you still are only using a conventional crude oil that is ultra refined.

Here is a list of the only Oils that are true full synthetic (groups 4 or 5).

Mobil 1, Amsoil, Royal purple, Redline, some Schaffers, some Motul, Valvoline synpower is a blend of goup 3 and 4, Castrol makes (1) full synthetic it is 0w-30 only and has to say made in Germany on the bottle otherwise it is group 3,the bargain oil out there is Valvoline maxlife synthetic blend which is group 4 and a group 2 blend it performs really well at a reasonable price.

ok Now YOU know the difference time to decide,

group 4 and 5 do outperform the others, but by how much ??? Oil has come an incredibly long way. No longer do we utilize crappy group 1 basestocks (at least not much). Now most convevtional oils in fact are group 2 group 3 mixes to meet ever tightening lubricant requirements and tests. The pseudo full synthetics which are group 3 and really good oils, one of the best is Pennzoil Platinum actually probably the best group 3 oil on the market.

My advice is to decide will you extend oil change intervals out 6-10,000 miles to make true use of the true full synthetic, do you subject your vehicle to severe conditions do you start your vehicle in subzero temperatures if so then synthetic may be your thing...........come on over to bob is the oil guy forum and learn much much more about oil........

As noted by others, synthetic oil is man made motor oil, whereas normal oil is made from refined petroleum. Where I would deviate from others comments is: a) synthetic oil does not "stick" to anything better; and b) use whatever grade oil your car manual says to use, not the old 1960s 10w30 winter, 10w40 summer, that is incredibly old info, and should only be heeded if your car is also that old; c) someone said never change brand or whatever, which is generally true, but less of an issue if you stay within the same brand (the additive chemistry between normal oil and synthetic oil do not change, they are more likely to change from one company to the next); d) one company's synthetic is not going to be particularly "better" than the next -- Amsoil and Mobil have been selling consumer market synthitic oil longer than anyone, but all the oil companies have had commercial grade synthetic oils for about the same length of time; e) last thing...changing oil less often...if your car is under warranty, follow manufacturer guidance, they don't care if you use synthetic, but will void your warranty in a heartbeat if you don't follow their maintenance plan. After warranty, do as you feel comfortable. I don't agree with extended oil changes -- it is true synthetic oil does not break down as quickly as normal mineral based oils, but the chemical additives get used up at exactly the same rate whether the carrier oil is mineral or manmade.

This is similar to another question I saw here.

Synthetic is a man made oil that lasts longer between changes than Regular petroleum Motor oils. 7000-10,000 miles between synthetic oil changes is not uncommon, as opposed to 3000-5000 miles on regular oil.

Determining the weight of oil. Depends on where you live and the type driving. In hot climates in the Southeastern and Midwest US, 10w40 is common for summer, and 10w30 for winter.

Heavy Oils up to 50 weight for extreme heat, or 20 weight for extreme cold is possible. Most people run 10w40 year round or switch to 10w30 in the fall and winter months.

20w50 is mainly for trucks or racing in extreme driving or long distance driving. You don't normally use that in the mini van or pickup truck tooling around town.

synthetic oil is man made and lubricates better than conventional oil, you can go 6 or 7 thousand miles before oil changes with synthetic, just use the same weight oil you now use but use the synthetic, there are a lot of good brand synthetics out there so you really can't go wrong, mobil 1, royal purple, and amsoil are a few of the best.

Synthetic oil has an oily substance that sticks better to the cylinder walls and all components. It is very effective for the life of your car. Regular oil does not have these ingredients. I would recommend you to switch to synthetic

Do NOT switch oil brand, type or grade. Stay with one, and do regular oil changes.

Different oil chemistries can react very badly with one another resulting in engine failure.

http://en.wikipedia.org/wiki/Synthetic_motor_oil

synthetic oils are more refined then reg. oil