Car Care

Synthetic Vs. Conventional Oil

Have you ever walked into the repair shop for an oil change and been offered a more expensive synthetic oil, but weren’t sure if the extra cost would be worth it?

If so, you’re not alone. According to a AAA nationwide survey, 44% of drivers are unsure or skeptical that synthetic oil is actually better for their engines. With so many mechanic upsells and a general distrust of the automotive industry among Americans, it’s easy to assume this is just another way mechanics can pad the bill.

Here at FIXD, our mission is to educate, empower and protect drivers. We decided to do some digging ourselves to find out more about the differences between synthetic and conventional oil. Keep reading to discover everything you need to know about conventional vs. synthetic oil so that the next time you go in for an oil change, you can feel confident about your choice!

Types Of Motor Oil

Motor oil is the substance used for lubrication of internal combustion engines. In other words, it’s the stuff that keeps your car or truck running smoothly, while cleaning, cooling, and protecting the engine.

Motor oils are divided into 5 major groups:

  • Groups 1 & 2 make up conventional oils derived from a petroleum base
  • Groups 3, 4, & 5 are chemically formulated synthetic oils (Group 3 still being derived from a petroleum base)

Regardless of the derivation, synthetic oils are engineered to have superior qualities compared to the conventional oils in groups 1 and 2. However, the answer to “is synthetic oil better than conventional oil” isn’t always a straightforward one.

Many factors go into picking the right oil for your vehicle, including your vehicle type, your personal driving conditions, your manufacturer’s recommendations, oil quality, and oil weight (viscosity).

To get started, we need to understand the key differences between synthetic and conventional oils.[/vc_column_text][vc_column_text]

What Is Synthetic Oil?

Synthetic oil is a man-made lubricant derived from chemically modified materials and typically a base of crude oil. Originally developed in 1929 as a substitute for petroleum-based motor oil, synthetic oils have been used throughout World War II and the 1970s energy crisis for better engine protection and fuel economy.

While some high-performance vehicles and jets, for example, require synthetic oil, many modern mainstream cars could also benefit from using synthetic oil. 

In fact, 70% of new cars get either fully synthetic or synthetic blended oil according to a Consumer Reports study of the 2019 model year.

Why are so many drivers choosing synthetic over conventional motor oil?

Benefits Of Synthetic Oils:

  • Ability to withstand higher temperatures and improve engine lifespan
  • Reduces engine wear in cold startups 
  • Superior chemical stability and engine protection
  • Lasts longer than conventional oil and is less prone to oxidation (which means fewer oil changes)

Bottom line: Synthetic oils are better at protecting a vehicle’s engine in extreme conditions and provide better protection against friction and wear.

There’s just one big catch…

Synthetic oils can cost 2-4 times as much as regular oils according to Consumer Reports. That cost can add up over the years, which is why synthetic blends were created.

Full Synthetic Vs. Synthetic Blends

Synthetic oil blends are just like they sound: A mixture of synthetic and conventional motor oil. If you go with this option, you’ll get a higher performance oil at a better value than full synthetic oil. However, synthetic blends don’t last as long as the real thing, so it may not pay off in the end.

Conventional Oil

To understand the performance differences between conventional and synthetic oils, first you have to understand how they are made. 

The oil we use in our cars today is multigrade oil, which must meet viscosity requirements at two temperatures in order to be suitable for year-round use. Conventional oil starts off with the properties of a monograde oil. 

To illustrate this, we will use conventional 5w30 oil as an example. The petroleum base oil alone has the properties of an SAE 5 grade oil. This means at low temperatures it is thick (viscous), while at high temperatures it is very thin. 

To ensure that the petroleum base oil can sufficiently protect the engine at high temperatures, oil companies use additives to make the petroleum base SAE 5 grade oil into a multigrade 5w30 oil. 

Pour point depressants are used to reduce the viscosity at low temperatures and viscosity index improvers can thicken the oil at high temperatures, thus producing 5w30! When brand new, conventional oil and synthetic oil behave exactly the same.

However, over time the chemical additives used in the conventional oil to change its properties begin to break down. As these additives start breaking down, the conventional 5w30 from our example starts to return to its original straight grade 5 base oil. 

As this happens, the oil thickens, causing used conventional oil to behave very differently from new conventional and synthetic oil. As you can see below, the used conventional oil on the left is much thicker and does not flow at the same rate as the new conventional oil, or the new or used synthetic oil.

Is Synthetic Oil Worth The Cost?

So, now you know the good, bad, and ugly when it comes to synthetic vs. conventional motor oils. But at the end of the day, is synthetic oil worth the extra expense?

Let’s look at some numbers.

The average cost of a conventional oil change is about $40, while a synthetic oil change costs closer to $70. If you want to change your oil yourself and save on labor, synthetic oil will still cost at least twice as much as conventional.

So, as the AAA found in their 2017 independent study, switching from conventional to synthetic oil will cost the average driver $5.33 extra per month ($64/year).

While we hate to say “it depends,” whether or not you should pay $60+ more per year for synthetic oil truly depends on several factors. Synthetic oil has been shown to provide better protection for the engine, which could help drivers save money in the long run by avoiding damage.

However, many of the same benefits can be reaped by simply getting conventional oil changes at the manufacturer’s recommended intervals.

One of the key benefits of using synthetic oil is that it lasts longer than regular oil; however, this also depends on the brand of oil you use, your driving style, and driving conditions.

When You Should Use Synthetic Oil 

If you drive a high-performance engine that relies on supreme performance and engine reliability, certain types of luxury sedans, an older vehicle prone to sludge buildup, you live in an area with extremely frigid temperatures, or you do a lot of towing with high loads and slow speeds, synthetic might make sense for you.

Otherwise, consider all the facts and weigh the pros and cons. For example, if you don’t plan on owning your car for years to come and you put synthetic oil in it now, you’ll be passing on most of the advantages to the next owner. But if you do plan to keep your car for the long haul, the superior lubrication can be worth it.

Oil Change Best Practices

Regardless of what type of oil you use, always consult your owner’s manual and follow the manufacturer’s recommended intervals for oil changes. 

Every time you start your vehicle, byproducts from combustion contaminate your oil and if these contaminants are allowed to build up, they can create damaging sludge in the engine. If ignored for too long, this sludge can cause engine failure.

With FIXD, it’s never been easier to keep up with routine maintenance! The FIXD Sensor and free app connects to your phone (Android or iOS) to automatically alert you when it’s time for your next oil change based on your specific vehicle make, model, and mileage. It also tells you when it’s time for wiper replacement, tire rotations, new battery, and much more. 

Oh, and it will instantly alert you to any engine problems and tell you what your check engine light means in plain English!

Never miss important maintenance or worry about getting taken advantage of at the repair shop again. Click here to learn more about this genius gadget called FIXD.


Wife, mom, Content Manager & Senior Copywriter at FIXD. From the garage to the gym, I love helping people learn and grow. Dream car: ‘69 Acapulco Blue Mustang.

Kate McKnight
Wife, mom, Content Manager & Senior Copywriter at FIXD. From the garage to the gym, I love helping people learn and grow. Dream car: ‘69 Acapulco Blue Mustang.

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    1. It would be helpful if the explanation of different grades of oil (5w-20, 0w-40) was also given.
      I thought that the “W” number was the cold rating and the number after the “-” represented the running temp viscosity. As such, a 0W-40 should do everything. So, why doesn’t every manufacturer just make that grade?

      1. I drive a 2009 Saturn outlook and I use quakerstate 10w30.. is okay to switch to a synthetic oil without doing any harm if so which weight and brand.. also is it harmful to switch back to conventional oil ?

        1. Yes you can change to synthetic oil and there are a lot of good manufactures out there to choose from like Mobile and Pennzoil which the latter is my preference. Keep in mind that once you switch to synthetic oil it is not advisable to change back to regular oil which can damage your engine. I even have switched my mower to synthetic oil due to the temps and hard work it has to do, so yes but beware that if you make the change you should not go back but it is a better oil.

          1. Switching back will do no harm to your engine. Not sure where you got that information

        2. • If conventional 10w30 is what your car’s manufacturer calls for, you can run the blends with no problems. Yes you can go back to regular oil. The only time you cannot ‘go backwards’ is when the manufacturer says to run a full synthetic. Never run anything but the synthetic in that case.

          •• My personal vehicle: 2005 GMC Safari Van, very close to max weight all the time with tools and supplies, change the oil every time a 5000 mile increment comes up on the odometer. My last oil change was at 360,000, next will be 365,000, then 370,000 etc etc. If you are late for one, be early on the next! Be as close to the numbers all the time and you won’t go wrong. A simple system!
          ••• BTW: Yes ORIGINAL engine and tranny!! I run Quaker State or Penzoil (SAME MANUFACTURER) 5w30 “Syn-Blend High Mileage”.

        3. I was a mechanical engineer with FRAM for a few years. Lab tests showed you can intermix conventional and synthetic, back and forth with no problem at all. Tests also shown that engines under lots of daily stress, (trucks, performance cars) benefitted from synthetic. A top grade petroleum oil in daily drivers give equal protection if changed around every three to five thousand miles.

        4. Synthetic oil and conventional oil are interchangeable anytime. You can blend them together as well hence some oil are semi-synthetic.

        5. We change oil in our 2 totals and our ’60 Corvette every 5,000 miles with Valvoline conventional oil. Factory recommendation of 10,000 miles allow too many contaminants to build up in the engine and in the oil filter.

      2. I driving a 2002 toyota sequoia and I use 10w30 it’s ok to change to synthetic oil

      3. Personally, synthetic oil is totally worth the extra expense. I drive my car for 5K miles between oil.changes without worries…

    2. I run synthetic in my car

      1. I run one with my car as well.

    3. I have a 2004 Dodge ram Quad cab 1500 with a 5.7 L engine in my truck has 190,000 miles on a strictly use synthetic oil and get my oil changed every 5000 miles including the filter I am very happy with synthetic oil’s preferably mobile one I have been using this product since it came on the market I suggest people use Synthetic oil’s especially on older cars with a lot of mileage thank you

    4. It’s only logical to use a better product in your home mileage car don’t you think everybody

    5. Synths can cause your seals to leak since the wear only designed for std oil on older vehicles

    6. I switch to synthetic oil once I reach 100,000 miles and sell the car at 200,000 miles.

    7. I use 10w30 regular oil in my 1989 190,000 mile jeep. Would it be beneficial to change to synthetic? I doubt it.

    8. I purchased 10 oil changes from my dealer for $ 400 when I bought my 2014 Hyundai Sante Fe Sport with a 2.0 liter turbo. I have considered using synthetic but have not done it for several reasons. As mentioned in the article synthetics tout being able to go many more miles between oil changes… The factory manual states oil changes need to be done every 6 months or 5000 miles. A warranty void could occur if I go past that, meaning I may get no advantage from the potential extra mileage. As the article states, potentially oxidizing combustion products will get in to the oil regardless of how long the oil can itself maintains its lubricant properties. Another potential issue is that service providers are so used to using their conventional oils that there is no guarantee that the mechanic will look at the paperwork and actually install the synthetic oil if it is purchased. If I were changing my own oil I would most likely use synthetic oil just for piece of mind. I don’t do a lot of my own maintenance anymore but have seen enough oil fouled plugs at well under 100 K miles that I would feel better about better lubricants being used.

    9. what kind of oil should I use on Dodge Sprinter 2007 V6 with 3.0 engine, diesel

    10. You didn’t mention the environmental differences between synthetic oil and regular oil. I believe synthetic oil is significantly better for the environment.

    11. It’s good to know that synthetic oil could provide better protection for your car’s engine, which would help you save money in the long run. As a new car owner, this is excellent information for me. From now on, I’ll make sure to use synthetic motor oil because of the things you mentioned in this article. Thank you very much!

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