Best Synthetic Oils: Invest in Your Engine’s Long-Term Health
What’s in your engine? Find out which synthetic oil is best for your ride.
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BY Norah Tarichia / LAST UPDATED ON April 21, 2021
Gone are the days when drivers solely relied on conventional motor oils for their vehicles. Their unpredictability, impurities, and in some cases, toxicity necessitated the need for synthetic oils as a game-changer in the industry. Synthetic oils were introduced to drivers in 1997, and although more expensive than the alternative, synthetic oils quickly gained a large following due to their consistency and superior performance in comparison.
Generally, most synthetic oils are better than conventional oils, but some synthetic oils perform better than others. This is because synthetic oil manufacturers have different formulations tailored for different operating conditions and engine configurations. We will have an in-depth look at the types of synthetic oils available so you can choose the best option for your engine.
This motor oil is an SAE 5W-30 formulation designed to offer maximum protection to your engine for about 10,000 miles.
- Promotes fast cold weather starts
- Improves fuel economy
- Lubricates the engine to reduce wear and tear
- Resists deposits and sludge build-up
- Not approved for some vehicle brands, such as Audi
Sporting a 5W-30 configuration, this motor oil offers about 40 percent more wear protection than most motor oils. It can be used on cars, SUVs, and trucks.
- Great high- and low-temperature protection
- Compatible with most conventional and synthetic oils
- Improves fuel efficiency
- Promotes faster oil flow for quicker cold starts
Recommended for gas engines, this 5W-30 synthetic oil offers optimal wear protection to your engine. It works on almost all types of vehicles, including ones with turbocharged engines.
- Promotes better fuel economy so you can drive an extra 550 miles per year
- Keeps your pistons cleaner for longer
- Lubricates and protects your engine
- Maintains efficiency and flow in both cold and extreme heat environments
- On the expensive side
- Doesn’t condition older seals
- May be harmful to the environment if disposed of incorrectly
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Best Synthetic Oils Reviews & Recommendations 2021
Best High-Mileage Synthetic Oils Reviews & Recommendations 2021
This is an SAE 5W-30 synthetic oil designed to improve efficiency and prevent emission system failure in vehicles with over 75,000 miles.
- Keeps the engine running clean by reducing sludge and harmful deposits
- Can help improve fuel economy
- Helps reduce leaks in older vehicles
- Might sometimes burn
- You need to use a heavy oil filter
This high-mileage oil helps to keep older engines that suffer from wear and tear cleaner and running for longer.
- Reduces sludge and deposit buildup
- Reconditions hardened or shrinking seals
- Lubricates moving parts to prevent damage
- Oil burn-off resistance decreases after 1,000 or 2,000 miles with the oil
- Shorter change intervals
This motor oil is designed to restore engine performance in high-mileage vehicles. It contains zinc and phosphorus additives for anti-wear protection.
- Prevents wear and corrosion
- Reduces friction for smoother engine performance
- Reduces sludge and harmful engine deposits
- A more expensive motor oil
Best High-Performance Synthetic Oils Reviews & Recommendations 2021
This oil is formulated for use in track cars and other vehicles with high-performance engines. It’s formulated with well-balanced additives that help with anti-wear protection.
- Includes a boosted level of zinc and phosphorus additives than other synthetic oils
- Reduces friction and increases engine horsepower
- Good burn resistance
- Not as good for high mileage vehicles as other dedicated options
This motor oil is formulated for high-stress applications such as towing or hauling vehicles or high-performance vehicles.
- Long drain interval of about 20,000 miles
- Resists degradation or oil breakdown even when under pressure
- Reduces friction on moving metal parts
- Comes with a tough protection seal that can be difficult to open
This is a semi-synthetic racing oil that‘s designed to withstand high temperature and extreme pressure conditions. It’s an SAE 10W-30 formulation.
- A good degree of resistance against viscosity and thermal breakdowns
- Contains strong detergents that clean the engine and make it run quieter
- Can lead to a smoother and more responsive engine
- More expensive than other general oils
- Bottle doesn’t come with a convenient handle
Best Synthetic Oils for Diesel Engines Reviews & Recommendations 2021
This is an SAE 5W-40 synthetic oil that can be used in both gas and diesel engines. It helps to reduce engine wear and promote better performance.
- Improves gas mileage
- Meets the demands of severe driving conditions
- Makes the engine run smoother and quieter
- A bit pricey
- Top nozzle is somewhat flimsy
Sporting an SAE 5W-40 configuration, this synthetic oil is designed to meet the demands of most European gas and diesel engine vehicles.
- Optimal protection from sludge and varnish deposits
- Great cold and hot weather protection
- Can be used on turbocharged vehicles
- Quality of the case is lackluster
- Cases can come from the factory with a broken seal
This synthetic oil formula is a solid option for turbocharged diesel trucks.
- Excellent hot and cold weather performance
- Can help improve horsepower and gas mileage
- Resists formation of sludge and varnish
- Won't prevent leaks in older engines
Best Synthetic Oils for Motorcycles Reviews & Recommendations 2021
A good synthetic oil designed for larger, more powerful bike engines used in high-performance riding.
- Engine noise reduction is noticeable
- Small gains in horsepower and fuel efficiency
- Ideal for wet clutch motorcycles
- Frequent oil changes are necessary to maintain performance gains
- Shorter shelf life than other motor oils
One of the best synthetic oils to choose for four-stroke engines. Noticeable gains with on- and off-road use.
- Good improvement with shifting quality
- Cooler running temperatures
- Variable results depend on the engine type
- Longevity of the oil is shorter than other options
A safe synthetic oil for 4-stroke motorcycles with catalytic converters. It’s formulated with ester technology for better engine response.
- Noticeable gains on first use
- Withstands extreme pressure conditions
- Great on- and off-road performance
- Leans on the expensive side
- Gains are somewhat unnoticeable in cold weather
Benefits of Synthetic Oil
- Extend engine life. The best synthetic motor oil is formulated to have a high degree of natural solvency, meaning it can clean and remove deposits. This keeps your motor sludge- and deposit-free so it can run as smoothly and efficiently as possible, as well as extend the lifespan of engine seals and other components.
- Maximize engine performance. There’s a reason why high-performance vehicles and race cars all run synthetic oil from the factory—superior engine performance. Enthusiasts often report that they perceive more power and torque from their engines when they use synthetic oil. At the very least, synthetic oil is slicker than conventional oil, so it’ll make your ride run smooth as silk.
- Improve fuel mileage. Premium synthetic oil reduces the amount of friction that occurs between key engine components, therefore making your engine run smoothly and efficiently. Theoretically, this increases the fuel mileage of your vehicle, so you’ll spend more time on the road and less time (and money) at the pump.
- Flows better in cold or hot weather. The proprietary formula of synthetic motor oil makes it flow better in extreme temperatures. During wintertime, its resistance to viscosity breakdown lets it flow freely regardless of how cold it is outside, so your car is less likely to break down due to cold starts. Alternatively, synthetic oil works at peak performance during hotter weather too.
- Longer lifespan than conventional oil. The best full synthetic motor oil has a considerably longer lifespan than synthetic blends or conventional oil. In some cases, full synthetic oil has a change interval of up to 15,000 miles, compared to 3,000 miles for conventional motor oil.
- Saves you money in the long run. Although going synthetic initially costs more per quart than conventional, it saves you money in the long run. Not only will you get more mileage out of engine components and save money on fuel, but you’ll also enjoy savings on less frequent oil changes. That’s something every motorist can get revved up about.
Types of Synthetic Oil
Full synthetic motor oil is created in a laboratory with a unique molecular structure and is infused with additives to deliver optimal wear protection and performance for your engine. Unlike conventional oil, it is not derived from whole crude oil, so it’s formulated without any of the impurities that you’d find in conventional oil. The best synthetic engine oil brands use a proprietary blend of anti-wear and cleaning additives to make your motor run at its best.
As the name implies, a synthetic blend motor oil is a mix of conventional oil and a brand’s synthetic base oil. Think of synthetic blend oil as a conventional oil fortified with synthetic supplements for better engine protection and performance. However, it’s worth mentioning that synthetic blends do not deliver the same caliber of performance and protection that a best-rated synthetic oil does. Still, if you choose not to spend a little more for full synthetic oil during your next oil change, you can rest assured knowing that a synthetic blend provides more benefits than conventional oil.
Founded in 1957, Liqui Moly is a German company that manufactures oils, lubricants, and additives. The brand prides itself on offering premium quality products at a more accessible price point than its competitors. One of its top products is the Longtime High Tech 5W30 Synthetic Oil.
Introduced in 1974, Mobil 1 offers synthetic motor oil and lubricant products. Its synthetic motor oil is perhaps the most recognized brand in the business, with prestigious auto manufacturers such as Porsche and Mercedes-Benz using Mobil 1 synthetic oil in all their vehicles. One of its best-selling products is the Extended Performance 5W-30.
Established in 1986, Royal Purple is an American manufacturer of lubricant products for automotive, industrial, marine, motorcycle, and racing usage. It is best known for its motor oil products and garners the endorsement of car enthusiasts for its high-performance formula. A particularly popular product is the High-Performance 5W-30.
Since its inception in 1866, Valvoline has gained a solid reputation in the car care industry as one of the best manufacturers of motor oils, additives, cleaners, and lubricants. This Kentucky-based company dedicates most of its efforts to making innovative products to improve the on- and off-road performance of motorcycles and vehicles. One of its popular motor oils is the Advanced Full Synthetic SAE 5W-30 Motor Oil.
Synthetic Oil Pricing
- Under $30: You’ll find a few options for under $30 for a 5-quart container, though most of these products are synthetic blends. Not all value-priced synthetic and synthetic blend motor oil brands are created equally, so make sure you scour our synthetic motor oil reviews to see which one fits your needs.
- $30-$39: The majority of synthetic motor oil products fall within this price range. You’ll find everything here, from high-performance motor oil to high-mileage oil. These options typically deliver a great mix of performance, efficiency, and value.
- $40 and up: Some of the best engine oil in the world resides at this lofty price point. These premium synthetic oil products promise the best engine protection, performance, and efficiency.
Viscosity grade is the most important factor in selecting the right synthetic motor oil for your needs. If you operate your car in a hotter climate or ring your engine out often, a viscosity of 10W-40 is best. For commuting in most warm or cold climates, a 5W-30 synthetic oil fits the bill. Finally, if you drive in conditions that could be described as arctic, a 5W-20 or even 0W-20 synthetic oil is advisable.
The labels on all types of synthetic oil list the specific application that the oil is designed for. Some common synthetic oil applications include higher mileage, extended performance, diesel engines, and motorcycles. Do your homework on your vehicle’s condition before you purchase the best synthetic oil for your needs.
Compatibility with Existing Oil
Before you add full synthetic engine oil to your ride, it’s important to note if the brand is compatible with other types of oil. If it isn’t, you’ll have to drain the existing oil before filling it up with the synthetic stuff. It’s also crucial to consult your owner’s manual to verify which type of oil your vehicle requires. For instance, most vintage vehicles were engineered to run best on conventional oil.
Each synthetic motor oil brand adds its proprietary blend of additives to enhance certain properties. For instance, viscosity-index improvers work extremely well in ensuring that oil doesn’t get too thin at higher temperatures. Other additives like detergents are efficient cleaning agents designed to remove deposits and sludge from your engine. Determine which additives would provide the benefits you need the most before purchasing a synthetic engine oil.
- Price. If you’re on the fence about plunking down the price premium that certain high-end full synthetic oil brands command, it’s completely understandable. Expensive synthetic oil brands aren’t always objectively superior to less expensive brands. Conduct your synthetic oil comparison and research reviews online to determine which synthetic oil is right for you.
- If you are upgrading to synthetic oil, also consider upgrading to a high-quality oil filter so you can better protect your engine from small metal flakes and other microscopic by-products of combustion that can accelerate engine wear.
- It’s important to carefully read the label of synthetic motor oil containers. These labels list essential information about the synthetic oil viscosity rating, application, and, sometimes, the additives it contains.
- Look for an American Petroleum Institute (API) rating donut somewhere on the synthetic oil container label. This seal of approval means that the synthetic engine oil has passed the API’s rigorous quality standards. To learn more about the API oil categories, click here.
- Before switching over to full synthetic oil, consult your vehicle’s owner manual to see if there are any break-in instructions to prep for the switchover. Also, make sure that the synthetic oil you intend on using is compatible with other types of oil. If it’s not, you’ll have to completely drain your existing oil before going full synthetic.
- If you’re not afraid to get your hands dirty and change your car’s oil yourself, ensure that you don’t overfill your engine’s crankcase with oil. Overfilled oil can rinse into the crankcase and cause air bubbles to churn into the oil. This can stress the engine components, cause overheating, and even foul the spark plugs.
- Check your oil at every other gas-up. For best results, run your car for 15 minutes then park it in a level place. Let it cool down for 15 minutes, remove the dipstick and wipe it with a clean rag. Reinsert the dipstick all the way, then pull it out to ensure the oil level is between the marks.
- If you plan on doing a lot of towing or racing with your vehicle, consider adding an oil cooler if your ride isn’t already equipped with one. Oil coolers function the same way your radiator does and can dramatically increase the lifespan of your engine.
Q: What does API SM/CF and SL, SJ, SH, SG mean on my oil container?
API sets industry-recognized standards for oil and petroleum products for passenger and commercial vehicles. The letters after API, like SM or SL, denote the quality of motor oil. Currently, the highest standard for passenger vehicles is SN. CF denotes a diesel engine or commercial vehicle standard, and the highest standard is CJ-4.
Q: Will I damage my engine if I switch from synthetic to conventional oil?
No, although you may experience a perceivable loss in protection, performance, fuel mileage, and longevity if you switch back to conventional oil. Be aware that some synthetic oil types aren’t engineered to be mixed with other oil types, so in this circumstance, you’ll have to drain your existing synthetic oil before adding any conventional oil.
Q: Do unopened bottles of synthetic oil have an expiration date?
This largely depends on the individual manufacturer of synthetic engine oil. Some brands claim that unopened containers of their synthetic motor oil have a virtually unlimited shelf life if stored under ideal conditions. Alternatively, other brands like Mobil 1 claim that unopened containers of their oil last up to five years. Read the label of your synthetic oil container for this information and always follow the manufacturer’s expiration date.
Q: Will synthetic oil cause my engine to consume more oil?
This is another commonly-cited myth about synthetic motor oil, and it’s also false. Synthetic engine oil in no way causes your engine to consume more oil compared to conventional oil.
Q: Is it true that some synthetic oil brands can last up to 15,000 miles?
Thanks to the innovative additives and other properties of modern synthetic motor oil, you really can follow the manufacturer’s recommended oil change interval without inflicting any harm on your engine. Note that the exact oil change interval may vary depending on your particular vehicle, so always consult your owner’s manual to make sure it doesn’t have a different recommended oil change interval.
From our review, we concluded that the Mobil 1 Advanced Full Synthetic Motor Oil is the best synthetic oil for engines that demand maximum protection. It retains its protective characteristics through thousands of miles of hard driving. If you are looking for a more budget-friendly option to keep your engine in top shape, then consider the Valvoline Advanced Full Synthetic SAE 5W-30 Motor Oil.