4 Worst Motor Oils Brands To Avoid (Keep Your Engine in Top Shape)

Motor oil is an important part of your vehicle’s engine. It lubricates the metal parts to reduce the amount of heat, protect against corrosion, and provide a smooth surface for the pistons and other moving parts.

Motor oil is a necessary part of your car’s engine, but not all motor oils are created equal.

Good motor oil makes your engine last longer and saves your gas mileage. Bad motor oil can damage your engine. Some manufacturers cut corners and produce a low-quality product that will provide you with less protection and lead to costly repairs down the line.

In this article, we are going to see what are the worst motor oil brands you must avoid at all costs. We’ll also see some good ones that will make your engine happy.

The Different Motor Oils

There are 5 main types of motor oils. Each one is best suited for a specific use case. For example, some perform better at low temperatures, while others are better at preserving older engines.

Let’s see them in more detail.

  • Synthetic motor oil—A synthetic motor oil is a high-quality product that provides excellent protection in your engine and lasts longer. They are best for new cars or engines with less than 100,000 miles on them.
  • Synthetic blend motor oil—This type of motor oil is a mixture of synthetic and mineral oils. They provide decent protection for your engine, but don’t last as long as pure synthetics. If you live in an area where it’s freezing during the winter months, this may be the best choice for you.
  • Mineral-based motor oil—Just like other types, mineral-based motor oils come in different grades. It is the cheapest one, but doesn’t last as long or provide excellent protection for your engine.
  • High-mileage motor oil—Motor oils labeled as high-mileage are designed for newer engines with over 75,000 miles on them. They’re slightly more expensive than the other types, but they last longer and provide better protection for your engine’s delicate parts. It is also known that high-mileage motor oil does not burn easily in older cars.
  • Conventional oil—These oils are made from petroleum and do not last as long. They also burn easily, which is why they shouldn’t be used in older engines or cars with high mileage on them.

What Makes a Motor Oil Bad?

To the untrained eye, all motor oils are the same. But each formula is different, which means it has specific characteristics.

The first thing you should check is your car’s manual. It will state what types of oil are the best for the car based on factors such as your driving style and the vehicle’s mileage.

Beyond that, here’s a rundown of what to look for in a motor oil.

API Symbols

The API (American Petroleum Institute) symbol is on every oil you buy. It shows the type of motor oil and its performance level.

  • S—This refers to the standard quality levels that meet minimum specifications for viscosity, flash point, rust inhibition, etc. You should look specifically for this symbol when buying your oils unless they say differently in your car’s manual.
  • I—This means that the oil has been tested for fuel economy and emissions in modern vehicles, which are equipped with catalytic converters. Your engine will run longer on higher-grade oils because they burn less easily.
  • C—API certified oils have passed extra tests to make sure they provide better protection against sludge, engine deposits and other problems.
  • SM—These oils have been tested for fuel economy in heavy-duty diesel engines. They provide better protection against soot, ash and carbon deposit formation and sludge compared to regular motor oil grades.
  • SL—Motor oils labeled with this symbol are ideal if you live in a tropical climate. They are made with a blend of base oils that have superior low-temperature characteristics, so they keep working when it’s freezing outside, especially at high altitudes.
  • B—These oils protect older engines with over 75,000 miles on them. They’re more expensive than regular motor oil grades but last longer and provide better protection.
  • CJ-I—This motor oil is made specifically for vehicles that have catalytic converters in them, which work on low-sulfur fuels only. If you drive a car with this type of converter, make sure the engine oil has this symbol on it so it doesn’t damage your system.


Viscosity is a measure of how thick or thin an oil is. High-quality motor oils are usually identified with numbers like 0W40, so the viscosity changes depending on outside temperatures. So you can use it of year without having to worry about your engine overheating in summer and freezing up during winter.

Viscosity Index (VI) is another important factor to consider. It shows how quickly an oil will reach its optimal temperature range under different conditions. A higher VI means the engine can achieve maximum performance even when it’s hot outside, which reduces emissions and fuel costs.

Oil Type

We already talked about this in the previous section, so we will not repeat ourselves. Check your owner’s manual to know if you should use high-mileage oil compared to your usual one. If you are unsure, consult a mechanic.

Additives in the Formula

Motor oils contain additives such as detergents and dispersants. They reduce the buildup of harmful particles in your engine, which means you can save money on maintenance costs over time, since these particles are often at the root cause of problems like clogged oil passages.

As far as this factor is concerned, look for motor oil that has high levels of anti-wear additives. This way you can make sure they protect your engine from damage and ensure it lasts longer, which is especially important if you drive a lot every day like with commercial vehicles.

Additives that might be included in motor oil are:

  • Anti-wear additives like zinc thiophosphate, calcium sulfonates. Their job is to provide protection against metal-to-metal contact inside your engine.
  • Detergent and dispersant additives like fercular, amine and alkenyl succinic acids. Their job is to keep harmful particles suspended in the oil so they don’t stick to walls of passages or other components.
  • Viscosity index (VI) Improvers like polyamide and polyolefin to improve viscosity index or quality of oil at higher temperatures. Also, viscosity modifiers like polyalkylimide glycols. They help reduce oil thickness or viscosity index improvers, which are already mentioned above.
  • Corrosion inhibitors like amines, oxides, esters. These help prevent rust from developing.
  • Demulsifiers like sulfonates to remove harmful particles in water that otherwise could cause corrosion inside your engine.
  • Anti-oxidants: phenol derivatives, Sulphur containing compounds and alkylphenols. These help the motor oil stay stable when exposed to oxygen for long periods of time at high temperatures. This helps improve the engine’s performance over time instead of deteriorating it like regular motor oil.
  • Pour point depressants: polymers and paraffin waxes. Poor weather can affect the quality of motor oil and its ability to maintain an optimal viscosity. These additives help keep it in liquid form when you need it most.
  • Anti-foamers or defoamers: fatty acid alkanolamide, esters of monoalkylphenol sulfuric acids. These help the engine by preventing foaming that can lead to serious problems over time, such as sludging, which is the accumulation of harmful particles in your oil.

All the compounds mentioned above are designed for specific, so you should look for motor oil with the ones that are right for your engine.

Warning: Additives that you should avoid in motor oils include excess phosphorus and sulfur compounds because they can damage the catalytic converter if your car has one, while nitrates can cause smog formation.

The 4 Worst Motor Oil Brands To Avoid

Bad motor oil is going to damage your engine severely. Only use these if you are in a pinch, are out of oil, and absolutely need a recharge. Also, do another oil change once you’re out of emergency.

Editor’s note: only buy oil that is API certified. Stay away from non-certified ones.

Here is a list of the worst motor oil brands out there to avoid:

Xpress Lube Pro

This oil is a disaster on all fronts. Not only it doesn’t meet any quality standard because of its low viscosity and lack of additives that protect the engine. It is actively harmful for your car.

This motor oil contains abrasive materials, according to an organometallic analysis conducted by the PQIA (Petroleum Quality Institute of America).

Xpress has service centers scattered across the US. Avoid them, because they’re likely to use this oil, which is going to kill your engine. Unless they’re your last option, then you should do a complete oil change as soon as possible.

Q10-40 Motor Oil

This oil is also a disaster. Much like many other oils on this list, it doesn’t have the additives to protect your engine from wear and tear over time, so you should avoid using it as much as possible for this very reason alone.

What’s even worse is how dirty it gets after being exposed to high temperatures because of its extraordinarily poor viscosity index. The viscosity of a fluid is the most important factor in determining how much drag it exerts on moving parts, so this oil will increase friction and cause damage to your engine over time because of its poor quality.

You should never buy Q10-40 if you care about protecting your car with high performing motor oils that don’t harm your engine.

Xcel Motor Oil

This is a very low-quality oil that doesn’t meet any of the important standards imposed by motor oil manufacturers and car companies across America, so it’s going to damage your vehicle over time because of its poor viscosity index and lack of additives.

It’s a very cheap product which has fooled many Americans into a purchase that harmed their car.

This product is so bad the company lost a class-action lawsuit over it.

Rev360 Motor Oil

This oil has so much phosphorus in it, that it can eat away at your engine and cause damage. Besides this, its viscosity index is very low, so the oil will become too thin when exposed to high temperatures, making it unable to protect your car from wear and tear.

You should stay away from this oil. It’s not worth spending your money on it since there are higher quality products out there that will keep your engine in optimal shape for a long time.

Still not convinced? Michigan banned it. That’s how bad it is.

The company doesn’t have a website, but you can buy its products online from websites like this one.

Which Oils Should You Use?

There are many high-quality motor oils out there. Here’s a list of the top three brands you should:

Lucas Oil

This company’s oil is API certified, so it meets all the standards set by car companies and manufacturers across America to make sure your engine doesn’t get damaged.

It’s a very high-quality oil that costs less than $15 for a gallon, which is pretty cheap compared with most brands out there, and its viscosity index ensures better protection of your engine across all kinds of weather.

Buy it here.

Mobil 1

This company makes excellent oil. It has a viscosity index that allows you to use the product for your whole car without worrying about damage over time because of its long-lasting protective qualities.

High-end car manufacturers like Porsche use it in their engines. Still not convinced? The product has over 16.000 raving reviews on Amazon.

If you’re looking for a durable oil that will keep your engine protected for thousands of miles, then Mobil 1 is the perfect choice for you.

Buy it here.

Amazon Basics Motor Oil

This is a very high-quality oil that is certified by American Petroleum Institute (API), which means it meets all the standards imposed by car companies and manufacturers across America to make sure your engine doesn’t get damaged over time because of being exposed to low-quality motor oils.

If you don’t particularly care about branding and want a solid product that will keep your engine working properly, then Amazon Basics is a great buy.

Buy it here.

How Oil Changes Affect Your Car

Changing oil is a necessary activity for your car, because of 2 reasons.

The first has already been mentioned above: how quickly an oil reaches its optimal temperature range under different conditions, which is known as the VI value and it’s measured by using a cSt viscosity test or kinematic viscosity test that measures the time required for one centimeter cube of oil to flow through a specific orifice at certain temperature.

The second factor is the oil’s ability to protect your engine against metal-to-metal contact, which happens when two surfaces rub together and it can affect performance over time because there are fewer moving parts in cars than trucks that require high viscosity oils because of their size.

Eventually the oil degrades (it won’t do its job) and then gums up engine parts. This is especially true in older or neglected engines.


Oil change is something everyone has to do with their car. And yet, many people have been fooled by companies that wanted to squeeze their customers by offering subpar products. Now you should know what to look for in a motor oil before your purchase.

Bad oil is going to cause extra strain on your engine, making it more prone to breaking. Good oil will make it run smooth for years to come, as long as you change it regularly.

Proper car maintenance will extend your vehicle’s lifespan. And, even more expensive motor oil is relatively cheap. You shouldn’t avoid paying a couple dollars extra for an oil change, since it’s such a crucial part of keeping your engine in top shape. You’re actually saving money in the long term.

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