The Benefits of Synthetic Oil vs Conventional Motor Oil
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Do the math for the make and model of your vehicle and the answer is “Yes, full synthetic oil is worth the additional cost” — if — it allows you to cut the # of oil changes per year in half. And still probably worth it, if you can cut the # of oil changes per year by a third.
Is this also true for synthetic blend oils? No, you will be paying more annually, with no good research to suggest you will or won’t make that investment back later.
By reading this article, you will get good, reference-based data to help you determine what is best for your Toyota, Honda, Ford, Dodge, Audi or other car brand.
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These are common oil change intervals for cars made after ~2016 To know the exact manufacturer’s for your make and model, it is recommended that you look in the owner’s handbook that came with your vehicle. European OEMs have recommended only full synthetic from about 2010. For most models the OEM recommends oil changes with conventional oil at 5,000 miles.
| OEM (2017-present) |
Conventional (miles) | Blend (miles) | Full Synthetic (miles) | Notes (primarily for full synthetic oils) |
|---|---|---|---|---|
| Toyota | 5,000 | 5,000 | 10,000 | Only if using 0W-20 full synthetic and normal driving conditions |
| Honda | 5,000-7,500 | 5,000-7,500 | 7,500–10,000 | Based on Maintenance Minder system using synthetic 0W-20 or 0W-30 |
| Ford | 5,000-7,500 | 5,000-7,500 | 7,500–10,000 | Assumes synthetic oil meeting WSS-M2C930-A spec; uses Intelligent Oil-Life Monitor |
| Chevrolet | 5,000-7,500 | 5,000-7,500 | 7,500–10,000 | Based on Oil Life Monitoring System; oil must meet dexos1 Gen 3 |
| Nissan | 5,000 | 5,000 | 5,000–7,500 | Applies to synthetic 0W-20 under normal use; more often in severe conditions |
| Hyundai | 5,000-7,500 | 5,000-7,500 | 7,500–10,000 | Assumes synthetic oil meeting API SN+ or better; varies by engine type |
| Kia | 5,000-7,500 | 5,000-7,500 | 7,500–10,000 | Follows same guidance as Hyundai; 0W-20 or 5W-30 synthetic |
| Mercedes-Benz | n/a | n/a | 10,000–15,000 | Synthetic only; must meet MB 229.5 or 229.51 specification |
| BMW | n/a | n/a | 10,000–15,000 | Synthetic only; BMW Longlife-01 or 04 oil required |
| Volkswagen | n/a | n/a | 10,000 | Requires VW 502 00 or 508 00 rated full synthetic oil |
Full synthetic oil has better durability and longer oil change intervals.
That high-mileage oils prevent or delay major engine repairs.
There is no independent or OEM-backed research confirming a reduction in the likelihood of repairs like gasket replacements or rebuilds. 
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That full synthetic oil dramatically increases engine life under normal use.
No long-term, large-scale field study compares engine lifespan of synthetic vs. conventional oil users in normal driving.
OEMs generally recommend full synthetic when engine design requires it, not for lifespan extension.
That synthetic blend is a meaningful upgrade for most drivers.
Most blends are created to meet minimum API standards at a lower price point—not for performance.
They offer no proven fuel savings and perform closer to conventional oil than to full synthetic.
Full Synthetic (“synthetic” in the table) means fewer trips to the auto shop.
If you are willing to spend ~$8 more in exchange for cutting your trips to the service station in half, then full-synthetic is an easy choice. You save time and take advantage of all the verified benefits that come from a higher performing oil; even if the actual benefits or payback isn’t clear. These benefits are just upside, where the true benefit is time savings.
This is true for your old or new vehicles.
Financial Model
| Year | Oil Type | Oil Cost ($) | Fuel Savings ($) | Repair Deferral ($) | Annual Cost ($) |
|---|---|---|---|---|---|
| 1 | Conventional | 150.0 | 0.0 | 0.000 | 150.000 |
| 1 | Blend | 240.0 | 0.0 | 0.000 | 240.000 |
| 1 | Synthetic | 200.0 | 42.0 | 0.000 | 158.000 |
| 10 | Synthetic | 200.0 | 42.0 | 966.913 | -808.913 |
Financial Model Assumptions:
| Oil Type | Fewer Oil Changes? | Why/Why Not |
|---|---|---|
| Conventional |  No |
Typically 3,000–5,000 miles. Breaks down faster. |
| Synthetic Blend | No |
Often still recommended at 5,000 miles by OEMs. |
| Full Synthetic |  Yes (many cases) |
Can last 7,500–15,000 miles depending on brand and vehicle. |
It is generally believed that full synthetic oils can delay small and major repairs. Delaying them by just one year saves a lot of money in Year 10, but you have to pay for it in Year 11 anyway. However, this delay, depending on when you sell a car, can mean full savings, especially if the repair is delayed for years.
Synthetic oils have superior additives in them that keep the oil in good condition over time. Typically, high performance vehicles require the use of synthetic oil.
Auto manufacturers are increasingly turning toward synthetic oils or synthetic blends (which are more affordable) because of the associated benefits.
Finding independent, non-industry-funded research that compares high-mileage synthetic oils to conventional oils in older vehicles is challenging. However, a study done by the American Automobile Association (AAA) in 2017 provides some insight:
AAA’s Findings: The study revealed that, on average, synthetic oils outperformed conventional oils by 47% in various tests, including those assessing shear stability, deposit formation, volatility, cold-temperature pumpability, oxidation resistance, and oxidation-induced rheological changes. newsroom.aaa.com
The claims are… Synthetic oil takes care of your engine better than conventional oil, according to information released by AAA. There are a number of benefits associated with using synthetic oil. For example, if you live in an area where it gets either very hot or very cold, synthetic oil helps to protect your car’s engine more effectively because it does not break down as quickly. If you have an older car, synthetic oil can keep sludge from accumulating in the engine, which can have disastrous consequences for your car.
Do you drive short distances? Conventional oil may break down more quickly because it just doesn’t have time to get hot enough to do the job it was meant to do. Also, if you carry around heavy material in your vehicle, synthetic oil is the better choice. It takes longer to break down, which means that it is more efficient for the work you are doing.
In addition to the benefits stated above, synthetic oil is popular because it lasts for a very long time. Years ago, you had to change your oil every three thousand miles. That has changed a little bit now, with some brands of oil lasting several thousand miles more than that. Synthetic oil takes things to the extreme, however. At minimum, you do not need to change the oil until you hit 15,000 miles, and some people believe you can go up to 25,000 miles. It is important to have an understanding of what the manufacturer recommends and then stick to that; for example, if it is recommended that you change the oil every six months, you should follow that recommendation.
While you need to make the decision on your own as to whether synthetic oil is worth the cost or not, there are a lot of advantages to using it. Not only does synthetic oil last longer than conventional oil, but it is good for the environment as well. At Ethan’s Honest Automotive, we’re happy to take a look at your vehicle and make recommendations for you. We’ll also handle all your oil changes and any other maintenance that you need on your car. Come see us today!
ETHAN'S HONEST AUTOMOTIVE SERVICE & REPAIR
Cache Valley:
Southeast Idaho
