Best Synthetic Oil for your Car – Reviews & Buyer Guide

Car owners know the importance of a well-oiled engine. It can add years to your car’s lifespan and miles to your adventures. It can be the difference between spending hundreds of dollars at the auto shop every few months and spending the same amount for car insurance.

Thus, you’re likely to search for new synthetic oil to get the best out of your car’s engine.

Synthetic oil is considered both the best and most expensive oil you can put in your car. But given the abundance of options available you might end up with one that isn’t fit for your car.

We’ve laid out all the information you might need here to find the best synthetic oil for your car. Browse through our list of the top rated synthetic oils and corresponding buying guide to help you make an informed decision. We’ve also included a short guide on how to change your engine oil yourself.

Top-Rated Synthetic Oils 2021

1. Mobil 1 120764 Synthetic Motor Oil , 5W-30

The ruling standard

Considered as one of the best synthetic oils in the market and often used as the standard upon which other products are compared to, the Mobil 1 line of fully synthetic oils has also been popular among car owners for many years. It passes plenty of industry standards and is the oil of choice among NASCAR teams.

Here we have its 5W-30 formulation which is designed to prevent the buildup of sludge and other deposits. Thus, providing efficient engine lubrication and wear protection. It also promises long-term use and high performance during maximum oil change intervals. The Mobil1 also promises exceptional performance for various types of vehicles in normal to extreme driving conditions.

Now, if this oil is good enough for the high standards of NASCAR teams, it sure is more than good enough for us!

Mobil 1 120764

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Recommended consumer applications:
Vehicles that require 5W-30 , Corvette approved

Industry Standards Passed:
ACEA, API, ILSAC, Ford, A1/B1, SN, SM, SL,SJ, GF-5, WSS-M2C946-A, WSS-M2C929-A


  • Great for quick cold-weather starting
  • Considered the best one in the market
  • Produces noticeable difference in engine performance


  • Needs changing at just every 4,000 or 5,000 miles

Mobil 1 120764 Synthetic Motor Oil 5W-30 YouTube Video Review

2. Castrol 03057 GTX MAGNATEC 5W-30 Full Synthetic Motor Oil

Constant protection from startup to turn off

Castrol oils are a fairly new contender in the US market. But this doesn’t mean that you should overlook their products.

If you have a vehicle which requires a 5W-30 grade oil, check out the Castrol 030057 GTX MAGNATEC. It’s a fully synthetic motor oil designed to protect your engine from the moment of startup/warmup at which time most engine damage can occur. But it doesn’t stop there, rest assured that your engine is still protected as it cools down after turning off.

It sets itself apart from its competition through its use of intelligent molecules. These molecules cling to vital parts of your engine to give them a layer of protection. They also significantly reduce engine wear and leave your engine running up to four times smoother than before.

Castrol 03057 GTX

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Recommended consumer applications:
All vehicles requiring 5W-30 grade oil

Industry standards passed:
No information found


  • Reduces startup noise
  • Effective for cold starts
  • Keeps engine well-lubricated
  • Value for the bottle content and price


  • Products produced before March 1, 2017 aren’t fully synthetic yet (check out your bottle’s manufacturing date before buying)

Review Castrol 03057 GTX MAGNATEC 5W-30 Full Synthetic Motor Oil YouTube Video

3. Mobil 1 120760 Synthetic Motor Oil 0W-40

The best synthetic oil for European brand vehicles

We have another one of Mobil 1’s oils on our best synthetic oil list.

This time it’s their 0W-40 European Car Formula. This fully synthetic oil is formulated from high performance synthetic base stocks to work with the latest gasoline and diesel engines. It has excellent low temperature performance for immediate engine protection at during startups. Not only that, it also promises to enhance frictional properties to aid fuel economy.

But perhaps most impressive is that the Mobil 1 0W-40 formula is the oil used as factory fills by many of the world’s finest cars. So, if you want to keep your BMW or Audi at peak performance, give this motor oil a go.

 Mobil 1 120760

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Recommended consumer applications: Most European vehicles (Mercedes-Benz, BMW, VW, Audi & Porsche), high HT/HS applications

Industry standards passed: API, ILSAC, ACEA, General Motors, Ford


  • Smooth and quiet startups
  • Perfect for high-end vehicles
  • Flexible formula can fit many vehicles (But be sure to check your manufacturer’s recommendations)


  • Users complained of getting bad 0W-40 re-blends

Mobil 1 120760 Synthetic Motor Oil 0W-40 Youtube Video Review

4. Valvoline 5W-30 SynPower Full Synthetic Motor Oil

Great synthetic oil for diesel engines and heavier vehicles

If you have a bigger vehicle, the Valvoline SynPower 5W-30 might be the best synthetic oil for you. It is specifically formulated to use with petrol and diesel engines of passenger cars, delivery vans, and light trucks. It is also suitable for vehicles such as minibuses and campers.

Its formulation includes antiwear additives to ensure protection against friction and wear especially during startups. 

The Valvoline SynPower 5W-30 promises to deliver protection from sludge and varnish to ensure that your car engine is well-protected. It also claims to reduce engine wear during high temperatures and improvement in viscosity stability. 

Valvoline Advanced Full Synthetic SAE

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Recommended consumer applications:
Gasoline and diesel engines of passenger cars, delivery vans, light trucks, person minibuses, campers.
Modern engines with turbochargers and catalytic converters.
Suitable for direct injected diesel engines.

Industry standards passed:
GM dexos 1™ Gen 2,
MB-Approval 229.5
VW 50200/50500
GM LL-A-025, LL-B-025 


  • Still works even after clocking in thousands of miles
  • Decreased oil burn-off rate when used with older engines
  • Reduces engine leaks
  • Efficient dissipation of heat and friction


  • Not much noticeable difference in performance with other synthetics

Valvoline Synpower 5W30 Youtube Video

5. Pennzoil 550022689 5W-30 Platinum Full Synthetic Motor Oil

A different blend for better cleaning performance

Pennzoil, a company of Shell’s, cuts themselves a share of the synthetic oil market by coming up with a product that stands out from the rest.

The Pennzoil 5W-30 Platinum oil’s main selling point is its infusion with Pureplus technology. This special technology is described as a ‘revolutionary gas-to-liquid process which converts natural gas into…a high quality full synthetic base oil’. Such process ensures a clearer and cleaner oil  than most crude oils. The oil’s formulation also includes additives to ensure complete engine protection.

Another product highlight of the Pennzoil 5W-30 Platinum oil is its claim of keeping pistons 30% cleaner than the industry’s required standards. Thus, this synthetic oil promises to keep your engine cleaner than any other synthetic oil can ever can.

Lastly, Pennzoil also promises better fuel economy with this synthetic oil. Expect to drive an extra 550 miles/year while using this special blend synthetic oil. 

Pennzoil Platinum Full Synthetic Motor

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Recommended consumer applications:
Chrysler MS-6395
Ford WSS-M2C929-A, WSS-M2C946-A
GM 6094M, 4718M, Dexos1
Honda/Acura HTO-06

Industry standards passed:
APO SN-RC and all previous categories
ACEA A1/B1-10, A5/B5-10, A1/B1-12, A5/B5-12


  • Successfully prevents engine sludge in sludge-prone vehicles
  • Makes engine run smoother and slightly more powerful
  • Makes engine quieter than Mobil 1 oils do
  • Easy cold-weather startups


  • a bit overpriced

6. Castrol 03101 EDGE 0W-40 A3/B4 Advanced Full Synthetic Motor Oil

Synthetic oil for maximum wear protection

We have another Castrol oil on our list. This time it’s the Castrol 03101 EDGE 0W-40 A3/B4 a fully synthetic motor oil formulated to provide the highest level of protection of critical engine parts.

One of its main selling points is its special formulation (the TITANIUM Fluid Strength TechnologyTM) which reduces volatility to protect important engine parts from wear. It does this through the minimization of breakdowns and production of deposits to keep engine internals clean.It is also touted to deliver a maximum horsepower of up to 40% longer than its competitors.

Owners of European brand cars will also be pleased to find that this synthetic oil will work very well with their engines.

Castrol 03101

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Recommended consumer applications:
Some models of Chrysler, Ford, GM, BMW, Mercedes-Benz, Porsche, Subaru and VW

Industry standards passed:
API SN; API SM; SL; SJ; CF; ILSAC GF-5*; ILSAC GF-4*; ILSAC GF-3*; ACEA A1, A2, & A3; ACEA B1, B3, & B4; ACEA C3


  • Performs well in difficult driving situations
  • Said to be as good as the Mobil-1
  • Works well for German cars
  • Competitive price point


  • Has many versions/blend variety (Be sure to check the labels before buying)

Castrol 03101 EDGE 0W-40 A3/B4 Advanced Full Synthetic Motor Oil

7. Shell ROTELLA T6 5W-40 Full Synthetic Diesel Engine Oil

A heavy-duty, fuel-saving synthetic engine oil

If saving up on fuel is your priority, the Shell ROTELLA T6 5W-40 may be the best synthetic oil for you.

This Shell fully synthetic oil offers an enhanced fuel economy saving of 1.5% (compared to 15W-40 oils) of fuel consumption without having to forego engine protection. It is also marketed as a heavy-duty engine oil which can resist heat breakdown in order to protect your car’s engine.

Another great thing about this synthetic oil is its outstanding stability. It can resist viscosity loss and can maintain optimal pressure in your car’s engine.

Shell Rotella T6

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Recommended consumer applications:
Particularly effective in modern low-emission, heavy-duty engines, especially those with exhaust after-treatment devices operating in extreme hot and cold conditions.

Industry standards passed:
API: CK-4, CJ-4, CI-4 PLUS, CI-4, CH-4; ACEA E9; JASO DH-2; Cummins CES 20086; Volvo VDS-4.5; Detroit Fluid Specification (DFS) 93K222, Caterpillar ECF-2/ECF-3, MAN M3575, JASO MA/MA2, Allison TES 439, MB-Approval 228.31


  • Non-spilling container
  • Versatile use (can also be used for motorcycles, bikes, mowers, etc.)


  • Difficult to pour

8. Valvoline 5W-30 MaxLife High Mileage Motor Oil

TOP-RATED synthetic oil for high-mileage vehicles

The Valvoline 5W-30 MaxLife is a synthetic blend motor oil specifically designed for high mileage engines. If you have a vehicle with 75,000 miles on it or more, this is a great choice for you.

It boasts of having a formula which blends synthetic and premium conventional base stocks along with additives like seal conditioning agents, anti-wear additives and extra cleaning agents. The seal conditioning agents refresh the car’s aging engine to prevent oil leaks. Meanwhile, the extra cleaners keep engines clean by removing sludge and other deposits. 

 Valvoline High Mileage

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Recommended consumer applications:
Petrol, diesel and LPG engines of passenger cars, delivery vans, light trucks, persons minibuses, campers
Specially developed for modern engines with higher mileage.

Industry standards passed:
GM dexos 1™ Gen 2; API Services SN/SM, Resource Conserving, ILSAC GF-5 and all preceding API and ILSAC gasoline categories


  • Helps keep seals soft
  • Noticeable difference in performance after use
  • Affordable


  • Oil easily turns a dark color even before the suggested oil change mileage

9. Royal Purple 51020 API-Licensed SAE 0W-20 High Performance Synthetic Motor Oil 

A synthetic blend oil with increased ethanol fuel compatibility

The Royal Purple 51020 0W-20 is a synthetic blend engine oil which features a patented additive technology which is said to prevent and lubrication starvation and white sludge in higher ethanol fuels.

It is also part of Royal Purple’s High Performance Synthetic (HPS) composed of street motor oils infused with their Synerlac additive technology for enhanced engine performance.

Royal Purple 51020

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Recommended consumer applications:
For use in both gasoline and diesel engines.

Industry standards passed:
API energy conserving


  • Gets the job done
  • Cost effective compared to other brands
  • Recommended by mechanics
  • Effective cleaner yet doesn’t darken fast


  • Not as effective as other famous brands

10. Royal Purple ROY11748 HMX SAE 5W-30 High-Mileage Synthetic Motor Oil

Reduces oil consumption in old, high mileage vehicles

Give your old car’s engine a much-needed boost and added care with Royal Purple’s HMX 5W-30 fully synthetic oil. It is designed to minimize the inside wear of older engines to restore it to its earlier and better performance conditions.

It also promises to effectively reduce oil consumption which is common in higher mileage cars using additives like stout detergents. These additives remove deposits that have built-up in your engine over the years.

 Royal Purple ROY11748

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Recommended consumer applications:
Recommended for any four-cycle gasoline with 75,000 miles or more

Industry standards passed:
API SL Service requirements for gasoline engines


  • Effective detergent, keeps filters gunk-free
  • Increases smoothness in engine operation
  • Decreases oil burn


  • A bit expensive
  • No noticeable increase in power

Buying Guide: Things To Consider

Synthetic oil is a specific type of oil formulated to ensure the highest level of lubrication in both low and high temperatures. This results in both better car engine protection and cleanliness. Its primary difference from other engine oils is that synthetic oil is not formulated from crude oil and thus, have fewer impurities which result in smoother performance.

The American Petroleum Institute classify oil into five categories: I and II are crude oil derivatives and III to V are classified as synthetic (although only IV and V are said to be ‘truly synthetic’).

Before we go in further, we’re reminding you that not all cars need synthetic oil. Most old cars run better on conventional engine oil. Synthetic oil is the best fit for newer car models. That’s why we specified which car models are fit to use with which synthetic oil brand and viscosity on our list above.

Now that we that out of the way, let's get started knowing the factors you should consider when choosing the best synthetic oil for your car.

Full synthetic oil vs. Synthetic blend oil

Debates between those who prefer full synthetic oil over synthetic blend oil and vice versa have been waged since both products’ introduction to the market in the 1960s. Now we’re not here to end the decades-long debate overall. But we can inform you about each product’s perks and downsides.

Full synthetic oil: This is generally considered the superior of the two. Full synthetic oils are specifically made for high-tech car engines. They tend to have a long-lasting performance with regards to viscosity index and protection against deposits. This type of oil is also recently being used more and newer car models are built to accommodate its use. However, full synthetic oil can be very expensive. Not to mention, not all car engines need full synthetic oils (like older car models). You can check out your car’s owner manual to find out.

Synthetic blend oil: This type of oil is a mix of natural oil (crude oil) and synthetic oil. This makes synthetic blend oils less volatile, evaporate less and reduce oil loss. Because of this, and their cheaper price compared to full synthetic oils, they are a popular choice among those who drive pickups and SUVs. However, choosing synthetic blend oils can also be a risk as they are not fully regulated. This means that there are no set standards about the concentration of mineral and synthetic elements found in synthetic blends. One must be very mindful of choosing a blend that will be suitable to your vehicle’s performance level.

Also Read: Comparing synthetic oil and regular oil

Viscosity and viscosity index

Another important thing to consider when choosing the good synthetic oil for your car is viscosity.

In simple terms, viscosity describes the oil’s resistance to flow as well as its thickness. An oil’s viscosity is expressed numerically as multigrades or mono-grades.

According to Popular Mechanics, a synthetic oil’s viscosity is rated at 0o F (the number before the letter ‘W’ meaning winter) and at 212o F (the second number).

Another useful term to know is viscosity index. It refers to an oil’s resistance to thinning out after an increase in temperature. A higher second number in an oil’s viscosity measure is usually a good indicator of an oil’s ability to avoid thinning.

For example, a 10W-30 synthetic oil has less viscosity at colder and hotter temperatures than an oil with a rating of 20W-50.

A viscosity of around 10W-30 is enough for most vehicles.  However, it is still better if you check what your car’s manufacturer recommends for your specific car model and the kind of weather your driving area usually gas.

The article answers some of the frequently asked questions comparing the engine oils used. Such as what's the difference between 5w30 and 10w30

Oil Classification Codes

Ensure the quality of the synthetic oil you’re getting by checking out what labels you can find on the container.

A reputable synthetic oil will have display certain symbols which indicate which industry standards it passes. Watch out for the American Petroleum Institute (API) donut which will indicate whether a synthetic oil passes the Energy Conserving test and show the Society of Automotive Engineers (SAE) viscosity number. Meanwhile, the starburst symbol signifies that the oil meets current engine protection standards set by the International Lubricant Standardization and Approval Committee (ILSAC).

You can find a more definitive list of API donut symbol codes here.

Oil Classification Codes


Additives are enhancing substances that may be added separately or are already present in synthetic oils to improve their performance. These additives are meant to help the oil maintain good lubrication, minimize sludge and varnish production and possible engine damage thinning oil may cause.
Here are some examples of additives and what they do:

  • Detergents:  Removes solid deposits, keeps surfaces clean, prevents deposits, rust and corrosion
  • Anti-wear agents: Protect metal surfaces, usually made of zinc diakyl dithiophosphate (ZDDP)
  • Viscosity-index improvers: Reduce synthetic oil thinning at high temperatures
  • Antioxidants: Prevents oxidation and oil thickening
  • Dispersants: Disperse solid particles to prevent sludge, acids and varnish
  • Foam inhibitors: Collapses bubbles formed by oil to keep oil a full-liquid stream
  • Friction modifiers: Reduce engine friction, improve fuel economy, examples are graphite and molybdenum
  • Rust and corrosion inhibitors: Secure metal parts against acids and moisture

When to change your car’s engine oil

Changing your car’s engine oil is one of the easiest yet most important maintenance chores you can do. And now that you’ve probably found the best synthetic oil for your car, you might as well do the dirty work of putting to use.

But first, you need to know if it’s the right time for an oil change. Mechanics advise that you watch out for these five signs:

  1. Your engine oil looks black and full of gritty (original oil color is honey brown)
  2. Your car engine emits louder noises than normal
  3. You can’t remember your last oil change
  4. Your check engine light is constantly on
  5. You can see a drop of your engine oil

 A more exact way of knowing when to change your oil engine is through miles run. The number will depend on your current engine oil and the state of your car’s engine. But newer cars, produced from the year 2013 onwards, are recommended to have their oil change every 7,500 to 10,000 miles ran.

If you’re planning to save a trip to your mechanic and doing the job yourself, you can find a hands-on tutorial on how to change your car oil here.

You maybe interested:


With all the available choices out there, you’ll surely find the best synthetic oil for your car.

 Just be sure to take things like your car’s current condition and your manufacturer’s recommendations and you’re already halfway ready to take your pick. Have a high mileage car? Or European model car? Do you drive at extreme temperatures? There’s a synthetic oil which blend will work for you!

We hope this guide helped you find the synthetic oil you’re looking for. Now, it’s time for that much-needed oil change.

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