Synthetic Oil vs. Conventional Oil: Which Is Better for Your Vehicle?
Synthetic Oil vs. Conventional Oil: Which Is Better for Your Vehicle?
There is a lot of debate surrounding full synthetic oil vs. conventional motor oil. Which one is better for your vehicle? And, more importantly, which one will give you the best performance? In this blog post, we will take a look at the differences between synthetic oil and conventional oil, as well as review some performance test results. We will also discuss why AMSOIL is such a great option when it comes to full synthetic oils.
What is Synthetic Oil?
It is a frequently asked question by motorists. Additionally, they inquire, “How is synthetic oil made?”
Certain individuals believe synthetic oil is not derived from crude oil or other fossil fuels. They believe that if all motorists switched to synthetic fuels, we would break our reliance on fossil fuels while also saving children, polar bears, and whales.
A noble notion, but a fallacious one.
While synthetic and conventional oils perform differently and are manufactured differently, they both originate from crude oil or other fossil fuels.
However, as you will see, they are still quite different. Let’s learn about Synthetic Oil vs. Conventional Oil: Which Is Better for Your Vehicle?
Automobile oil, whether conventional or synthetic, is composed of two basic components:
The base oils are primarily responsible for resistance to wear, heat reduction, and friction reduction. The addition of various chemical additives to the formulation improves the performance of the motor oil. Chemical additives inhibit chemical breakdown, neutralize acids, and provide additional wear protection, among other functions, depending on the formulation and application.
Consider a quart of oil as a glass of lemonade. The water serves as the base oil, while the lemon concentrate and sugar serve as the additives.
For now, let’s forget about the additives and focus on the base oils to answer our first question, “What is synthetic oil?”
How Traditional Base Oils are Manufactured
From crude oil, the base oils used to produce conventional motor oil are distilled.
There are hundreds of different hydrocarbons present in crude oil. Using heat, pressure, and other catalysts, oil refineries separate crude oil into various products, including…
- Gasoline
- Jet fuel
- Diesel fuel
- Heating oil
- The base oils used to formulate conventional motor oil
However, distillation has its limits. Several of the molecules in crude-derived base oils are detrimental to the lubrication of an automobile’s engine. As a result, the performance of the oil and your engine suffer. In fact, the limitations of distillation became apparent during a pivotal battle of World War II, which aided in the defeat of the Axis powers and accelerated the development of synthetic oil.
Here you can read about the history of synthetic oil.
How Differently Synthetic Base Oils Are Made
Instead of being distilled, synthetic base oils are chemically synthesized (i.e. built).
What does this imply?
Refiners reduce the molecules of crude oil to their fundamental constituents through a series of chemical reactions. Then, using only identical molecules (typically ethylene), they construct synthetic base oils from scratch. The outcome is a pure base oil that lacks the irregular molecules present in conventional base oils distilled from crude oil.
Unless you are a chemist, this is somewhat confusing, so let’s use another analogy.
Suppose you purchased an old Victorian home. It is rich in personality, but it has seen better days. The roof is leaking, the foundation is cracked, the plaster is worn, and the walls are out of plumb. You decide to make repairs.
Understanding Synthetic Base Oils and how they made
There are two approaches: the conventional approach and the synthetic approach.
The Conventional Method
You decide to live with the crooked walls after repairing the foundation, the cracked plaster, and the worn shingles. The renovation is not perfect, but it is cost-effective, and the house should provide reliable shelter for a few years before requiring additional work.
Synthetic Method
Instead of covering up the obvious flaws, you disassemble the house piece by piece.
Each shingle, piece of siding, nail, brick, stud, and joist is removed. Soon, the house’s components will be distributed throughout the yard.
The house is then reconstructed from the ground up using only straight studs and joists, good bricks, pristine shingles, etc. The final product is significantly stronger and more durable than the “traditionally” renovated home.
In a similar fashion, formulators disassemble crude oil molecules into their fundamental constituents and then, via organic synthesis, construct synthetic base oils using only the molecules that are, so to speak, “straight, square, and in excellent condition.” The resulting product is optimized for engine wear, heat, and stress protection.
This analogy applies to synthetic base oils derived from polyalphaolefin [PAO], but not to synthetics derived from Group III base oils. Not all groups of synthetic oil are created equal.
Is Synthetic Oil Superior to Conventional Oil?
Yes They Are!
If you’ve read this far, you can figure out the solution on your own.
Synthetic motor oil is manufactured using pure, standardized chemicals. As such, it provides advantages that conventional motor oils cannot match. It makes total sense. An automobile engine, a smartphone, a pair of shoes – you name it – will perform better and last longer if it is manufactured with superior components.
Test of Synthetic Oil versus Conventional Oil
However, you should not take our word for it.
The American Automobile Association (AAA) conducted a study to determine whether synthetic oil actually outperformed conventional oil and warranted the higher initial cost.
Following the synthetic oil versus conventional oil test, John Nielsen, managing director of Automotive Engineering and Repair at the American Automobile Association, stated:
“Oil protects vital engine components, and AAA found that synthetic engine oils performed 47 percent better than conventional oils in a variety of industry-standard tests. AAA’s findings indicate that, due to its superior resistance to deterioration, synthetic oil is particularly advantageous for newer vehicles with turbocharged engines and for vehicles that frequently operate in stop-and-go traffic, tow heavy loads, or operate in extreme heat or cold.
These conditions apply to virtually every motor vehicle on the road today.
AMSOIL’s own testing against conventional oil validates the findings of the AAA. As an example…
In the ASTM D5800 Noack volatility test, AMSOIL Signature Series 5W-30 showed 38 percent less oil consumption than the conventional oil tested, requiring less frequent top-offs.
AMSOIL keeps engines 81 percent cleaner (five times cleaner) than conventional oil by resisting deposit formation more effectively (supported by TEOST 33C test [ASTM D6335]).
Advantages of Synthetic Oil
AMSOIL and the AAA have established that synthetic oil outperforms conventional oil in tests. Consequently, what advantages can motorists anticipate when switching to synthetic oil?
Enhancements to Engine Safety
Protection from wear is the most sought-after feature of motor oil by drivers. If motor oil could make a car fly, but not prevent components from wearing out and failing, it would serve no purpose.
Synthetic motor oil protects against engine wear more effectively. It forms a thicker fluid film to prevent metal components from rubbing and wearing against one another. It also provides enhanced resistance to heat and loss of viscosity, two characteristics that translate to enhanced wear resistance.
Want proof? Compare the performance of AMSOIL Signature Series Synthetic Motor Oil to that of the industry’s leading synthetic-blend motor oil (more on synthetic-blends later)
What About Diesel Engine Protection?
Again, the evidence demonstrates the superiority of synthetic motor oil in protecting diesel engines from wear.
AMSOIL Signature Series Max-Duty Synthetic Diesel Oil offers six times the engine protection required by the Detroit Diesel DD13 Scuffing Test for Specification DFS 93K222 when 5W-30 is used as a worst-case example.
Enhanced Cold-Temperature Efficiency
When the temperature drops, motor oil thickens and moves more slowly, leaving portions of the engine temporarily unprotected. It is especially problematic with conventional oils because they contain cold-solidifying waxes.
Synthetics, on the other hand, lack waxes, so they remain more fluid in cold temperatures. This means that synthetics can reach vital engine components more quickly, offering more immediate engine protection and reducing wear. Simply put, synthetic oils provide superior protection against the cold.
Watch the video to see for yourself.
Better protection from high temperatures
Engines get hot. In fact, turbochargers and direct fuel injection, which help automakers meet today’s strict fuel-economy standards, have made them run hotter than ever.
Turbos can spin up to 300,000 rpm, and the exhaust gases that drive the turbine can reach 1,000ºF (538ºC). When the high speed and high heat come together, deposits can build up. This is called “turbo coking,” and it can ruin the turbo. When oil is left in the turbo and the engine is turned off while still hot, this is called “turbo coking.” The heat inside the turbo cooks the oil, which leaves deposits.
Check out the picture. That glowing chunk of metal is a turbocharger.
AMSOIL'S Signature Series Synthetic Motor Oil
That won’t happen if the motor oil does its job. And regular oils just aren’t good enough for the job. They are made of light, unstable molecules that turn into vapor when exposed to very high temperatures.
Synthetics, on the other hand, can handle extreme heat better, so they are a better choice for the hot engines of today. In fact, turbo protection is so important that General Motors’ GM dexos1® Gen 2 motor oil specification only recommends oils that pass its Turbo Coking Test.
We wanted to find out how well AMSOIL Signature Series Synthetic Motor Oil worked. How well did it work? Check it out yourself.
Maximum Fuel Economy
We’ve already talked about how regular oil gets thicker when it gets cold. Thick, cold oil is not only bad for wear protection, but it also wastes energy. Because of this, the engine has to use more fuel. Synthetic oils save the most fuel because they flow easily at start-up.
Also, low-viscosity oils like 0W-20 are easier to move than the 10W-40 oils that cars used to use. This, in turn, makes the car use less gas. But synthetic base oils must be used to make low-viscosity oils that protect your engine well in all the important places.
Reductions in Oil Use
There are several things that can make your engine use more oil. Most of them are mechanical, like…
- Problems with leaking gaskets or seals
- Clogged or worn piston ring
- Bearings that have been worn out or damaged
- Clogged PCV valve
If your engine leaks oil because of a mechanical problem, you should take it to a mechanic to get it fixed.
But the volatility of motor oil can also make people use more oil. The amount of a lubricant that evaporates is called its volatility. The more likely it is for a lubricant to evaporate and leave the engine through the crankcase ventilation system, the more volatile it is.
The more it evaporates, the less oil there is to protect the equipment, and the more often it needs to be replaced.
Most lubricants evaporate at low temperatures because they are made of small, light molecules. To get out of the solution and into the air, these light molecules need less energy in the form of heat than heavier molecules.
Volatility affects more than just how much oil is used
When heat makes light parts of oil evaporate, the oil gets thicker. This thicker oil makes the engine work harder, which leads to a number of problems, such as:
- Performance loss
- Fuel economy loss
- Poor starting in cold weather
- More deposits in the engine
The solution is to use an oil that doesn’t break down in heat and doesn’t get used up. Synthetic oils have a natural resistance to heat and volatility that is better than natural oils. So, they help you use less oil, which keeps your engine clean and running well.
In the Caterpillar-1N oil consumption test, for example, AMSOIL Max-Duty Synthetic Diesel Oil uses up to 76% less oil than the API CK-4 standard requires.
This graph shows that AMSOIL also cuts the amount of oil used in gasoline engines.
How often should synthetic oil be changed?
Because it works better, it makes sense that synthetic motor oil will last longer than regular oil. That’s right, but how long does synthetic motor oil last?
It depends on the oil and how you run your machine.
In general, synthetics work better than regular oil, but some synthetics are better than others. So, some things will last longer than others.
Most synthetics can last between 8,000 and 10,000 miles. But some synthetics today can go up to 25,000 miles or a year before they need to be changed. In normal service, AMSOIL Signature Series Synthetic Motor Oil is guaranteed for 25,000 miles or one year or 700 hours, whichever comes first. If you change the oil once a year, you waste a lot less oil and packaging. Also, it takes less time and costs less money to change the oil.
The quality of the oil helps decide how long it will last
The quality of its base oil and additives determines how long it can last.
It also depends on whether the conditions you’re driving in are considered severe or normal.
Too much idling, a lot of towing, hauling, or plowing, or driving in dusty conditions are all bad things that can shorten the time between oil changes.
We suggest that you change your oil according to the instructions in your owner’s manual or on the motor oil label.
Some synthetics are suggested for longer drain times than what is written in the owner’s manual.
By extending drain intervals in this way, you can safely change the oil less often and save money on oil over time, if you want to.
One example is the AMSOIL Signature Series, which was already mentioned. AMSOIL Signature Series Max-Duty Synthetic Diesel Oil, which is the same kind of oil for diesel engines, is another. In some situations, it’s recommended to use it for up to three times as long as the original equipment manufacturer says, but not for more than 60,000 miles/600 hours of service or one year, whichever comes first. Check out how often AMSOIL oil should be changed here.
The best way to find out how long your motor oil can last is to look at how long it has been used. It involves sending a sample of the oil to a lab, where technicians check it for wear metals, coolant, fuel, and other contaminants.
When to Change Synthetic vs. Conventional Oil
Remember the oil change at 3,000 miles? Some quick lubes and shade-tree mechanics may still recommend the practice as “cheap insurance” against engine wear.
It’s great that you want the best for your engine, but throwing away perfectly good motor oil helps no one (except the company selling you the new oil).
In the 1970s, quick lubes took the 3,000-mile oil change interval and made it longer (many of which were owned by oil companies). Even if they were thinking about what was best for their customers, it didn’t hurt that this made sure they would come back.
Those times are long gone.
Cars no longer need to have their carburetors adjusted, their ignition points replaced, or their batteries filled with water. They also don’t need oil changes every 3,000 miles (barring extreme operating conditions).
Motor oil technology has grown at the same rate as car technology, so most motor oils today last longer than the standard 3,000 miles. As was already said, some synthetics let you extend the time between oil changes, which saves you time and money.
Can Conventional Oil be mixed With Synthetic Oil?
Yes, you can mix conventional oil and synthetic oil together.
Putting them together won’t hurt anything. For example, synthetic-blend motor oil, which you can buy at any auto parts store, is just a mix of conventional and synthetic oil already in the bottle. But it is not something you want to do. Read on to find out why.
Unless you have no other choice, mixing conventional and synthetic motor oil is not a good idea. If you’re on the road and notice that your engine is low on oil, for example, the gas station next to the road may only sell conventional oil. In these situations, you should drain the oil as soon as you can and replace it with synthetic motor oil.
What is Synthetic-Blend Motor Oil?
We hinted at the answer above: it’s just motor oil that’s made with both conventional and synthetic base oils. Semi-synthetic is another word for synthetic-blend motor oil.
Synthetic-blend motor oils are in the middle of the range of motor oils, between conventional oil and synthetic oil. The idea behind them is to give drivers a taste of the better performance of a full synthetic oil at a price closer to that of a conventional oil. Oil marketers see them as a “stepping stone” product that will help get drivers to switch to a full synthetic in the long run.
When it comes to synthetic-blend motor oil, the most important question is, “How much “synthetic” is in my oil?” Does the 1 percent synthetic base oil in the oil in the bottle come from synthetic oils? 10 percent ? 30 percent ? You can’t find out.
TWEET THIS
Find out more about “How much “synthetic” is in my oil” in this post.
The better the oil should work, the more synthetic it has.
Full Synthetic Oil vs Synthetic Blend
Unfortunately for drivers, there are no industry standards or rules that say how much synthetic material must be in a synthetic blend for it to be called that. It depends on the manufacturer, and they’re not going to say because doing so would give their competitors an edge.
So, if you want to figure out how much and what kind of synthetic base oils are in your synthetic-blend motor oil, you can look for a few clues.
Find the technical data sheet for the oil on the website of the company that makes it. This is also called the “product data sheet.” Look for the part that says “Typical Technical Properties” or something similar. Keep an eye out for these two:
- Viscosity Index: Oils with a higher number have a better synthetic base oil that protects important parts over a wide range of temperatures by keeping the fluid thick and creating the necessary fluid barrier between parts.
- Pour point: is the lowest temperature at which oil can still flow and is used to measure how fluid it is when it is cold. A better synthetic base oil is likely to have a lower number.
You should know, though, that an oil’s performance isn’t just based on how its base oil is made. The additives also play a large role in fighting wear and deposits.
Product Code: ASMQT-EA
Engineered for enthusiasts seeking maximum protection and performance. Precision-formulated with cutting-edge technology and a longstanding devotion to making the world’s best motor oil. The result: engine protection that blows the doors off the highest industry standards.
• 50% more cleaning power vs. AMSOIL OE Motor Oil
• Ideal for turbos & direct injection
• Guaranteed protection for up to 25,000 miles or 1 year
Product Code: ALMQT-EA
Engineered for enthusiasts seeking maximum protection and performance. Precision-formulated with cutting-edge technology and a longstanding devotion to making the world’s best motor oil. The result: engine protection that blows the doors off the highest industry standards.
• 50% more cleaning power vs. AMSOIL OE Motor Oil
• Ideal for turbos & direct injection
• Guaranteed protection for up to 25,000 miles or 1 year
Product Code: ALMQT-EA
Engineered for enthusiasts seeking maximum protection and performance. Precision-formulated with cutting-edge technology and a longstanding devotion to making the world’s best motor oil. The result: engine protection that blows the doors off the highest industry standards.
• 50% more cleaning power vs. AMSOIL OE Motor Oil
• Ideal for turbos & direct injection
• Guaranteed protection for up to 25,000 miles or 1 year
Product Code: AZOQT-EA
Engineered for enthusiasts seeking maximum protection and performance. Precision-formulated with cutting-edge technology and a longstanding devotion to making the world’s best motor oil. The result: engine protection that blows the doors off the highest industry standards.
• 50% more cleaning power vs. AMSOIL OE Motor Oil
• Ideal for turbos & direct injection
• Guaranteed protection for up to 25,000 miles or 1 year
Product Code: ASLQT-EA
Engineered for enthusiasts seeking maximum protection and performance. Precision-formulated with cutting-edge technology and a longstanding devotion to making the world’s best motor oil. The result: engine protection that blows the doors off the highest industry standards.
• 50% more cleaning power vs. AMSOIL OE Motor Oil
• Ideal for turbos & direct injection
• Guaranteed protection for up to 25,000 miles or 1 year
Product Code: ATMQT-EA
Engineered for enthusiasts seeking maximum protection and performance. Precision-formulated with cutting-edge technology and a longstanding devotion to making the world’s best motor oil. The result: engine protection that blows the doors off the highest industry standards.
• 50% more cleaning power vs. AMSOIL OE Motor Oil
• Ideal for turbos & direct injection
• Guaranteed protection for up to 25,000 miles or 1 year
Product Code: ATMQT-EA
Engineered for enthusiasts seeking maximum protection and performance. Precision-formulated with cutting-edge technology and a longstanding devotion to making the world’s best motor oil. The result: engine protection that blows the doors off the highest industry standards.
• 50% more cleaning power vs. AMSOIL OE Motor Oil
• Ideal for turbos & direct injection
• Guaranteed protection for up to 25,000 miles or 1 year
