Motor oil provides crucial lubrication and protection for the myriad of moving parts in your vehicle’s engine. That said, you have to choose the right kind of motor oil to ensure that your engine stays healthy. Not all motor oil brands are created equal, and using a subpar product can lead to serious damage to your vehicle. Let’s take a look at the leading motor brands that you should avoid and the reasons why.

What Are The Leading Motor Oil Brands to Avoid header image

Why Does Motor Oil Brand Matter?

Oil brand matters because using a trustworthy brand lets you know that you are getting quality oil that will help with performance and longevity. That said, not all motor oil is created equally. Each motor oil brand incorporates its unique blend of additives and chemicals, which can have a significant impact when done right but can wreak havoc when done wrong.

Using a low-quality motor oil brand can result in long-term and expensive damage to your engine. This risk of damage is caused by a couple of things:

  • Inadequate lubrication. Low-quality oil may not provide sufficient lubrication, leading to increased friction between engine components. This friction can cause excessive wear and tear on critical parts, including pistons, bearings, and camshafts.
  • Poor heat dissipation. Without heat absorption, your engine will overheat, causing warped cylinder heads and damaged gaskets.
  • Sludge formation. Low-quality oil may contain impurities and lack effective detergents and dispersants. This can lead to the formation of engine sludge, which can clog oil passages and reduce the flow of oil to critical engine components.
  • Increased friction. When low-quality oil fails to reduce friction effectively, the engine’s moving parts can grind against each other, causing increased friction and wear.
  • Poor additives. Poor-quality oils may lack essential additives, making them less effective at protecting the engine against wear, deposits, and oxidation.

What to Look For in a Motor Oil

If you are looking for the difference between good and bad motor oil, you only need to look at a couple of factors:

1. Viscosity Index

Viscosity is a vital property of motor oil that determines the thickness or thinness of it. The figure out viscosity, you look at the numbers like 5W-30 or 10W-40. The first number (e.g., 5W) indicates the oil’s viscosity in cold weather, while the second (e.g., 30 or 40) reflects its viscosity at high temperatures. Viscosity matters, because it helps your engine adapt to various temperatures. If the engine oil you use does not have the correct viscosity, it could impact the overall performance of your vehicle.

2. Oil Type

There are several different kinds of motor oil:

  • Conventional Oil: Conventional motor oil is derived from crude petroleum. It’s suitable for some older vehicles but tends to burn more easily than other types. It may not be the best choice for high-mileage engines or those with specific performance requirements.
  • Synthetic Oil: Synthetic motor oil is a man-made lubricant composed of advanced chemical compounds. It excels in newer vehicles with less than 100,000 miles and generally lasts longer than conventional oil. Synthetic oil offers superior performance in extreme temperatures and under heavy loads.
  • Synthetic Blend Oil: Synthetic blend oil is a mix of synthetic and mineral oil. It strikes a balance between cost and performance and is a good option for vehicles in cold environments.
  • High-Mileage Oil: High-mileage oil is specifically designed for engines with over 75,000 miles on them. It contains additives that can help protect aging engine parts and extend their life.

3. Additives

Additives are extra chemicals that motor oil companies incorporate into their products to enhance performance. High-quality motor oil brands use advanced additives that help prevent the buildup of deposits and maintain the oil’s viscosity across a wide temperature range. On the other hand, low-quality oil does not contain additives. Or, the additives tend to be volatile.

Volatility tends to reduce the effectiveness of the oil and may also cause damage to your engine.

4. API Symbols

The American Petroleum Institute (API) assigns ratings to motor oil brands based on their performance and quality. Look for oils with an API rating of SP or higher, as these oils meet the latest industry standards. API ratings signify that the oil has undergone rigorous testing to ensure it provides adequate protection and meets emission standards.

If you want to find a highly-rated oil, look for the API symbols on the bottle. The symbols look like “API SP” or “API SN.”

What Are The Leading Motor Oil Brands to Avoid?

Now that you know what to look for in motor oil, let’s explore some of the leading motor oil brands to avoid:

Xpress Lube Pro Motor Oil

Xpress Lube Pro is a brand that is notorious for its poor oil quality. In fact, Xpress Lube Pro motor oil has gained a reputation for making false claims. Reports also indicate that Xpress Lube Pro contains abrasive materials that cause wear and tear. Since the oil is of low quality, it may also cause deposits of contaminants throughout the engine, reducing performance. If a service center uses this brand, stay away from it.

Liberty Motor Oil

Liberty Motor Oil is known for having a viscosity that is significantly lower (70%) than accepted industry standards. This low viscosity can be problematic, especially when exposed to high temperatures. Another reason to avoid Liberty motor oil is its lack of proper SAE grading.

Questron Motor Oil

Questron Motor Oil has faced criticism for misleading marketing practices. It falsely claims to meet API SN/GF-5 standards through deceptive packaging, which can mislead consumers. Furthermore, this oil lacks sufficient additives such as Calcium, Zinc, and Phosphorus. As a result, it may not provide adequate engine lubrication, leading to issues like clicking noises and increased engine wear. Questron is also highly volatile, making it more prone to evaporating at higher temperatures, reducing its overall effectiveness.

Q10-40 Motor Oil

Q10-40 Motor Oil lacks any API rating and does not meet essential oil certifications. This absence of industry certifications raises concerns about its quality and performance. It has been reported that Q10-40 may lead to accelerated wear due to its thin viscosity. It also contains a high amount of phosphorus, leading to more corrosion.

Bullseye Motor Oil

Bullseye Motor Oil is known for its thin consistency and low resistance, leading to insufficient engine lubrication. It may not provide the protection your engine needs. Also, Bullseye has a limited number of additives. This means that Bullseye cannot resist sludge deposits as well as a more reliable brand.

Quaker State Q Motor Oil

Quaker State Q Motor Oil is not only of poor quality but also comes with a higher price tag compared to better-quality motor oils. Please do not fall for its claim of being a multigrade oil. When tested, this claim was proved false. In fact, Quaker State Q is volatile and dissolves rapidly.

Xcel Motor Oil

Xcel Motor Oil is another motor oil brand that doesn’t meet the requirements of modern engines. Its quality and specifications fall far short of what is necessary for today’s vehicles. Using Xcel motor oil has been associated with increased engine dirtiness.

Everclear Motor Oil

Do not fall for the labeling. Everclear Motor Oil employs deceptive labeling by suggesting it’s a 5w30 multigrade oil when it is not. Also, the oil contains a high level of organometallic additives that may not be suitable for most engines. Additionally, it may be contaminated with used oil or engine coolants.

Petrola Motor Oil

Petrola Motor Oil is one of the worst motor oil brands you can find for your modern vehicle. This oil is specifically formulated for vehicles manufactured before 1930, making it wholly unsuitable for modern engines with advanced specifications and requirements. Not only is the oil itself problematic, but even its labeling and packaging don’t comply with the Fair Packaging and Labeling Act (FPLA). This lack of compliance raises concerns about product quality and transparency. 

The oil also contains limited additives and tends to become volatile when exposed to high temperatures—exactly what you don’t want from your motor oil.

Final Thoughts on Motor Oil Brands to Avoid

What are the leading motor oil brands to avoid? That would be Xpress Lube Pro, Questron Motor Oil, Liberty Motor Oil, Q10-40 Motor Oil, Petrola Motor Oil, Quaker State Q Motor Oil, Bullseye Motor Oil, and Everclear. These motor oils risk your engine and fail to meet industry standards. To safeguard your engine and ensure its longevity, it’s imperative to choose a reputable motor oil brand that adheres to industry standards, possesses the right viscosity, includes high-quality additives, and bears the appropriate API ratings. Your engine deserves the best care, and avoiding these leading motor oil brands is a crucial step toward achieving optimal performance and durability.

Categories: Oil Guides


Hi, I’m Alastair. Welcome to, a website for the best oil recommendations for your vehicle, whether it is a two-door sports car, SUV, hatchback, or tractor. Having grown up on a family farm and working as an engineer, I became interested in just about anything with an engine. I also found that motor oil, despite being essential for internal combustion engines, is overlooked, underestimated, or just misunderstood. There may come a day when motor oil is obsolete as electric vehicles become more and more popular. But until then, you are going to need to know the best type of motor oil for your vehicle. That is why I was inspired to create this website. aims to be the internet’s destination for everything related to motor oil, including news, comparisons, features, and recommendations for vehicles by make and model. All the information you need to keep your treasured vehicles running clean is right here. In particular, I am also obsessed with the upkeep of vehicles in general. That is why you will also find troubleshooting tips for removing oil filters and drain plugs, for example. Consider it the mission of to provide accurate information, as well as insight for automotive professionals and enthusiasts.


Leave a Reply

Avatar placeholder

Your email address will not be published. Required fields are marked *