Everything you need to know about synthetic oil

We’ve compiled everything you need to know about synthetic oil in one place, focusing on making it easy to understand so that you can make an informed decision.

What’s the synthetic difference?

Oils are grouped into different classifications depending on their method of extraction, as well as their origin. All of these base oils are slightly different.

Group I oils are the cheapest, and undoubtedly the least refined. They’re separated from petroleum stock through a solvent washing process, which leaves them with a high impurity content and they’re no longer used as motor oils in any capacity.

Group II oils are extracted partially through a process called hydrocracking. This removes the majority of the impurities, this oil is much cleaner but is still considered a mineral oil legally.

Group III oils ride the line between conventional and synthetic oils, they are produced exclusively through hydrocracking and can legally be called a “synthetic” oil since it’s been modified from the initial feed stock so much. They have a much higher viscosity index than Group I and II oils as well as a low amount of contaminants.

Group IV oils are produced from polyalphaolefins, which can be sourced either from an initial petroleum base or from a few biological sources. This kind of oil is definitely synthetic, and is modified substantially from the initially extracted molecules.

Group V oils are produced from any other type of feedstock, resulting in a wide array of different properties. Quite often, these oils are used as detergents or other modifiers added to Group IV or V oils to produce a product which is perfect for certain needs.

For the most part, synthetic oils are going to be modified Group III or IV oils. As a general rule, the advantages come in from two main places: purity and design.

Purity of synthetic oils

Synthetic oils, by their very nature, have a much lower instance of impurities. In some cases they won’t have any impurities at all.

Oil doesn’t actually “wear out”, instead it’s individual components within the oil oxidizing and becoming sludge which makes an oil less useful for lubrication as time goes on. While it’s impossible to avoid some contamination within a system which uses oil, such as slivers of metal, if the oil in question contains less contaminants in the first place it’s destined to have a longer lifespan.

What we think of as “oil” is actually a complex mixture of hydrocarbons and waxes, not a pure substance in and of itself. This is the big place where synthetic oils come in: by separating, processing, and purifying the individual components of an oil before recombining them.

This means that the process which produces synthetic oils is entirely repeatable, resulting in reliable, contaminant free oils which will perform the same pretty much no matter what. While the guidelines for mineral oils keep them fairly consistent, they’ll still have initial contaminants from their petroleum sources.

Specificity

Synthetic oils are “built”, not simply present. While most oils have additives before they reach the end consumer, synthetic oils can be tailored especially for a purpose based on the data which the manufacturers have.

This means that a synthetic motor oil isn’t “just” oil, but instead is a special combination of oils and additives which is built from the ground up to be used in engines.

The designer quality is highly desirable in the modern world, especially as engines become more advanced and thus require the utmost in lubrication to maintain the correct performance curve.

These qualities, especially the additives, carry over to their use in earlier engines as well as the oil is made to higher specifications than were initially found in the oils of decades past.

What advantages does synthetic oil offer?

While it’s much more costly, synthetic oils boast more than a slight advantage over conventional motor oils.

They’re pretty easy to explain for the most part.

• Longer lifespan-Since synthetic oils are more pure in the first place, they usually last for at least twice as long as their conventional counterparts. In some cases they can last for even more, depending on the engine in question.
• Greater performance-It’d actually be more correct to say “less reduced performance” but synthetic oils offer quite an advantage here. Since they’re generally a better lubricant in the first place, they cause an engine using them to function with less drag.
• Increased fuel efficiency-For the same reason as a lessened impact on performance, synthetic oils can also improve fuel efficiency. Less drag means more energy going to the wheels and less energy being wasted.
• Better performance at extreme temperatures-Synthetic oils tend to perform much better at the extreme ends of their operating ranges due to their composition. This applies to both heat and cold.
• Less volatile-It’s inevitable that some oil is going to evaporate in the high-temperature environment of a motor. Synthetic oils are formulated to evaporate less, which means you’ll be topping off the oil much less frequently.
• Reduced wear and tear-Due to the more fluid nature of synthetic oils, there’s less damage to the engine as it runs. The exact amount is up for debate, but it follows that a better lubricant will keep an engine running for longer.
• Less clogging-Since there’s less contaminants to oxidize and harden within oil lines, you’re looking at an oil which will clog much less over time.

All of these qualities are tied to the differences we pointed out above, and combined they lead to a pretty awesome difference over time.

Picking a synthetic oil

Knowing which synthetic oil to use has two factors to it, the SAE number and making sure that you find a true synthetic oil and not something labeled that way through a legal loophole.

SAE numbers

The SAE number on your oil is something of a mystery to many people. How do you know, after all, whether 5W-30 synthetic oil or 0W-20 is the right one for your engine?

Apart from the owner’s manual, there are also extreme conditions which sometimes require individuals to use a different oil. A basic layman’s understanding of synthetic oils thus becomes important.

Almost all synthetic oils come in a dual-grade. This will be in an XW-X format, such as 5W-20 synthetic oil.

In this case, the first rating is the “winter” rating of an oil, which shows how the oil performs compared to oils at 100°C(212°C). The second number indicates the grade of the oil at 100°C.

The grade of the oil isn’t directly tied to Viscosity Index(VI) but instead to a grading system so it’s comparative for the most part. Lower numbers mean the oil flows better for the most part.

If you’re in an area with extreme cold, then you’ll already know how much lower you need to go, but most modern oils can handle the usual fare. You’re best off just using what the vehicle manufacturer recommends: if the manual says 5W-40 synthetic oil, then stick that in there unless you’re planning on an arctic expedition.

“Full synthetic”

Due to a legal loophole, Group III oils are frequently labeled as synthetic oils. While they are quite altered from the crude feedstock they come from, it’s a bit of a misnomer.

A true synthetic oil is generally a Group IV oil combined with Group V additives in order to form a “true synthetic” oil. PAO oils have an even bigger advantage over Group II oils(the most common conventional oil) than Group III oils.

Unfortunately, if you live in the United States, it can be hard to ensure that you end up with a true synthetic oil. A court ruling in 1997 upheld the right of oil manufacturers to label Group III oils as synthetic.

Unfortunately, there’s no regulations requiring the labels to say anything about it on the bottle, so you’ll have to do careful research yourself to ensure you’ve got the best oil for your motor.

Environmentally friendly?

There’s some debate as to whether synthetic oils are actually more environmentally friendly or not.

The truth is this: Group III oils are hard to make the argument for. Group IV oils are still usually derived initially from a petroleum source, but PAO can be sourced from biological sources although only a scant few brands actually do so.

The impact is pretty much the same, in that they’re mostly derived from petroleum sources.

However, synthetics offer one big advantage: their lesser volatility means less topping off.

That means less oil is expended in between full oil changes. Indeed, synthetic oils have less than half of the volatility of conventional oils in many cases.

The fact that they last, at a minimum, twice as long as their conventional counterparts also means that they have the potential to reduce demand for oil overall, which is good for the environment as a whole.

So the advantages that synthetic oils offer the environment are quite indirect, but still give them a leg up on the conventional stuff.

Of course, pretty much any oil can be recycled with the proper techniques, and synthetics are no exception there. While many companies still require them to be separated from conventional oils, as we’ll see in a minute it’s really not necessary.

The myths of synthetic oil

Some of the false facts which surround synthetic oils are simply out of date, and others are just “common knowledge” that no one really seems to know where they emerged from.

The most prominent myth about synthetic oil is that it can’t be mixed with conventional oils. This… well, it’s false. Everyone has seen “synthetic blends” on the shelves before, which is exactly that: a conventional and synthetic oil mixed.

There’s simply no reason why you shouldn’t be able to mix them in the oil in your engine. They’ll be pretty much fine, although you may miss out on some of the advantages which are offered by true synthetic oils.

And yes, you can go back to using conventional oils if you decide that synthetic is too costly for your motor during your next oil change.

The second prominent myth is that synthetic oils tend to bust seals and gaskets, causing leaks in older vehicles.

There’s a kernel of truth in this: synthetic oils can cause leaks to appear and the older, ester-based synthetic oils were pretty hard on seals. Modern formulations aren’t, however, but they can demolish deposits left behind by conventional oils and cause problems which were plugged previously to appear.

If there’s any problems with the seals, the lower viscosity of synthetics can also cause problems. The thinner oil is undoubtedly going to break through any problems without mercy, so if you’ve got an older vehicle you may want to keep an eye on things if you switch to a synthetic oil.

Conclusion

We hope that we’ve filled you in on the differences and advantages which can be offered to you by synthetic oils. It’s a bit complex for the layman, but once you have a solid grasp you’ll be able to make an informed choice the next time you go in for an oil change.

The truth is: love them or hate them, synthetic oil is here to stay. More and more manufacturers are producing their engines specifically for these high-grade oils and it’s inevitable that the older oils are going to be slowly phased out in favor of the superior qualities of synthetics.