Here’s The 6 Best Penetrating Oils For Your Car

Penetrating oil is a low-viscosity lubricant used to loosen rusted, seized, or stuck metal parts. It works by infiltrating into small spaces between threads and other tight spaces, dislodging rust and corrosion, and facilitating easy removal or movement.

It’s an essential tool in any mechanic’s arsenal, whether you’re a DIY enthusiast or a professional. But with the vast array of options on the market, choosing the best penetrating oil can be a daunting task. This blog post aims to ease your selection process by highlighting the top six best penetrating oils available today.


Top 6 Best Penetrating Oil

1.     WD-40 Specialist Penetrant Spray

WD-40 is a household name, trusted by professionals and hobbyists alike. Their Specialist Penetrant Spray is specifically designed to break free stuck parts and protect against rust and corrosion. With its Blaster ProStraw, it ensures precise application.

2.     Liquid Wrench L106 Penetrating Oil

This penetrating oil is excellent for breaking through rust, corrosion, and deposits. It is safe to use on all metals and alloys. Its special formulation ensures effective penetration and long-lasting lubrication.

3.     Kano Kroil Penetrating Oil

Known as the “oil that creeps,” Kano Kroil penetrates minute spaces, dissolving rust and effectively freeing metal parts. It’s ideal for any mechanical maintenance or restoration project.

Kano oil with sway bar links and bushings.

4.     B’laster 16-PB Penetrating Catalyst

The B’laster Penetrating Catalyst is not just a lubricant but a surface conditioning product. It can break free rusted or frozen parts by attacking rust and corrosion at the molecular level.

5.     CRC 03027 Knock’er Loose Penetrating Solvent

An industrial-strength penetrant, CRC Knock’er Loose quickly penetrates rust and corrosion, lowering the friction to ease disassembly of mechanical components.

6.     Sea Foam BBG1 Bugs B Gone Multi-Use Cleaner

While not typically considered a penetrating oil, Sea Foam BBG1 serves as an effective rust penetrator and multi-use cleaner, especially useful for dissolving bugs, dirt, and debris from various surfaces.

Remember, the best penetrating oil for you largely depends on your specific needs. It’s essential to consider the specific application, the materials you’re working with, and the severity of the rust or corrosion.

Benefits of Penetrating Oil

Loosens Rusted Parts

The main benefit of penetrating oil is its ability to seep into the tiniest crevices and dissolve rust and corrosion. This makes it possible to loosen and remove rusted-on bolts, screws, and other parts that might otherwise be impossible to budge.


While its primary function is to penetrate and break down rust, penetrating oil also serves as an effective lubricant. This makes mechanical operations smoother and reduces wear on moving parts.

Protects Against Rust and Corrosion

Many penetrating oils leave behind a protective layer that helps prevent future rust and corrosion. This is particularly useful in machinery or vehicles that are frequently exposed to moisture.

Using a spray lubricant on car parts.


Penetrating oil can also be used as a cleaner. It can remove dirt, grease, grime, and other contaminants from metal surfaces, helping to maintain their appearance and function.


Penetrating oil can be used in a wide range of applications, from home repairs to automotive maintenance to industrial machinery maintenance.

Types of Penetrating Oil

1.     Aerosol

Aerosol penetrating oils are extremely convenient to use. They come in a spray can that makes it easy to apply the oil, even in tight spaces. They are ideal for tasks that require a large spread, like loosening a rusted bolt or lubricating a hinge.

2.     Non-Aerosol

Non-aerosol penetrating oils are applied by pouring or using a brush. They are typically thicker and offer a longer-lasting effect. They’re great for tasks that require precision and control.

3.     Food Grade

Food grade penetrating oils are designed for use on machinery used in food processing. They are safe to come into contact with food and won’t contaminate it.

4.     Industrial Grade

Industrial-grade penetrating oils are made for heavy-duty applications. They’re often stronger and more durable than other types of penetrating oil, making them perfect for use on industrial machinery.

5.     Multi-Use Cleaners

Some penetrating oils are also designed to serve as general-purpose cleaners. They can help dissolve dirt, grease, and grime from a variety of surfaces.

When choosing the right penetrating oil, consider your specific needs and ensure the oil is appropriate for the materials and conditions of your project.

Penetrating Oil Pricing

The price of penetrating oil varies widely based on factors such as the brand, the size of the container, and the specific formula. Here is a general idea of the cost:


These options typically cost between $5 to $10. They can be effective, but may not last as long or work as quickly as more expensive options. An example is the WD-40 Specialist Penetrant Spray.

WD-40 specialist penetrant being sprayed under the car.


These oils usually cost between $10 to $20. They often offer a balance between cost and effectiveness, and might include options like the Liquid Wrench L106 or the CRC 03027 Knock’er Loose Penetrating Solvent.


These products typically cost over $20 and sometimes much more. They usually feature advanced or unique formulations and might last longer or work more effectively than other options. Kano Kroil Penetrating Oil falls into this category.

Best Oil for Stuck Bolts

The Kano Kroil Penetrating Oil is often recommended as the best oil for stuck bolts. Its low viscosity allows it to seep into the smallest cracks and crevices between threads, helping to dissolve rust and loosen stuck bolts more effectively than many other options.

However, every situation is unique, and other oils may work better depending on the severity of the rust or other factors.

Best DIY Penetrating Fluid

For those who prefer a DIY approach, a mixture of acetone and automatic transmission fluid (ATF) is often recommended. This mix is praised in many DIY circles for its ability to break down rust and free stuck parts. To create this mixture, simply combine equal parts of acetone and ATF in a suitable container.

Here’s A Brief Step-By-Step Guide:

A man mixing chemical components.
  • Purchase acetone and automatic transmission fluid. Both of these products can be found at any auto parts store.
  • Find a suitable container. You’ll want a container with a lid, as this mixture should be stored carefully.
  • Mix equal parts of acetone and ATF. For example, if you use one cup of acetone, you should also use one cup of ATF.
  • Shake or stir the mixture until it’s thoroughly combined.
  • Apply the DIY penetrating fluid to the stuck bolt or part. Allow it to sit for some time (an hour or even overnight) to penetrate the rust before attempting to loosen the part.

Please remember, safety first: Always use gloves and eye protection while handling and mixing these chemicals, and use in a well-ventilated area.

Is WD-40 the Same as Penetrating Oil?

WD-40 is often confused with penetrating oil due to its wide variety of uses, one of which includes loosening rusted or stuck parts. However, traditional WD-40 is not the same as a dedicated penetrating oil.

The standard WD-40 is primarily a water displacement spray that has some lubricating and rust-dissolving properties. Its name, in fact, stands for “Water Displacement, 40th formula” – it was the 40th attempt to create a formula to displace water and prevent corrosion.

While it can sometimes help to loosen rusted parts, it is not specifically designed for this purpose and might not work as effectively as a dedicated penetrating oil, particularly in more severe cases.

However, WD-40 does produce a product specifically designed as a penetrating oil, known as the WD-40 Specialist Penetrant Spray. This product is formulated to penetrate into tight spaces, break up rust, and free stuck parts, much like other penetrating oils.

Does Penetrating Oil Really Penetrate?

Yes, penetrating oil does penetrate into small spaces between parts. It has a low viscosity, which means it flows easily and can seep into tight gaps more effectively than thicker oils.

When applied to a rusted or stuck part, it infiltrates into the tiny spaces between the rust and the metal, and between the threads of screws and bolts. Once inside these spaces, it helps to dissolve rust, dislodge dirt, and reduce friction, making it easier to loosen or remove the part.

The effectiveness of a penetrating oil can vary based on several factors, including the severity of the rust, the specific design of the part, and the quality of the oil. Some oils may also include additional ingredients to improve their penetrating ability, such as solvents to dissolve rust or corrosion inhibitors to prevent future rusting.

In some extreme cases, penetrating oil might not be enough to free a severely rusted part. Additional methods, such as heat or manual impact, might be needed. But in many cases, a good penetrating oil can make a significant difference in loosening stuck parts.

What Are Some Of The Essential Benefits Of Using Penetrating Oil?

Penetrating oil comes with numerous benefits that make it an indispensable tool in any mechanical setting. The primary benefit is its ability to seep into tiny crevices to dissolve rust and corrosion, making it much easier to loosen or remove stuck or rusted parts. It also functions as an effective lubricant, ensuring smooth operation and reducing wear on moving parts.

Besides, many penetrating oils leave a protective layer that helps prevent future rust and corrosion, particularly useful in machinery or vehicles that are frequently exposed to moisture. Penetrating oil can also serve as a cleaner, capable of removing dirt, grease, grime, and other contaminants from metal surfaces.

Lastly, it’s incredibly versatile, finding use in a wide range of applications from home repairs to automotive and industrial maintenance.

What Distinguishes The Different Types Of Penetrating Oil?

There are various types of penetrating oil designed for different uses and applications. Aerosol penetrating oils are easy to use, thanks to their spray cans which allow for application even in tight spaces. Non-aerosol oils, on the other hand, are applied by pouring or using a brush. They’re generally thicker and offer more durable effects.

Food-grade penetrating oils are safe for machinery used in food processing, while industrial-grade penetrating oils are ideal for heavy-duty applications, providing stronger and more enduring solutions. Some penetrating oils double as multi-use cleaners capable of dissolving dirt and grime from a range of surfaces.

How Does The WD-40 Specialist Penetrant Spray Stand Out From The Regular WD-40 Product?

While regular WD-40 has various uses, including some rust-dissolving and lubricating properties, it isn’t specifically designed to penetrate and free severely rusted or stuck parts.

The WD-40 Specialist Penetrant Spray, however, is a specialized product designed specifically to get into tight spaces, break up rust, and free stuck parts, which makes it function more like a traditional penetrating oil.

What Role Does The Viscosity Play In The Effectiveness Of Penetrating Oil?

Viscosity refers to a fluid’s resistance to flow. Penetrating oil has a low viscosity, which means it flows easily, even into tight gaps. This property allows the oil to seep into the minuscule spaces between rusted or stuck parts, where it can then work to break down rust and reduce friction, making it easier to loosen or remove the part.

What Factors Influence The Price Of Penetrating Oils?

The price of penetrating oils can vary significantly, influenced by factors such as the brand, the size of the container, and the specific formula. The brand name can often impact the price, as trusted and established brands may charge more for their products.

The size of the container is another factor, with larger quantities generally costing more. Finally, the specific formula can influence the price, with specialized or unique formulations often costing more than standard ones.

Is It Safe To Use A DIY Penetrating Fluid?

Yes, it can be safe to use a DIY penetrating fluid, but safety precautions must be taken. The commonly recommended mix of acetone and automatic transmission fluid (ATF) should be handled with care.

Always use gloves and eye protection when mixing and applying these chemicals, and ensure you are in a well-ventilated area. Also, remember to store the mixture in a suitable container with a tight lid, away from heat or flame.


To sum up, penetrating oil is a versatile and essential tool for any mechanical work, whether it’s loosening rusted bolts or maintaining industrial machinery. With various types available, including aerosol, non-aerosol, food-grade, and industrial-grade, you can find a product to meet nearly any requirement.

However, it’s vital to select the one that aligns best with your specific needs and tasks. By understanding the characteristics and uses of different penetrating oils, you can ensure you are equipped to handle any challenges you encounter, making your work easier and more efficient.

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About Brock Rangel

Hi, I am Brock, and I am the lead editor/photographer for TheCarColony. I have been a mechanic for over 14 years now, and I am here to spread my car knowledge across the web!