8 Best Penetrating Oil Reviews With Helpful Information 2018

Do you have bolts and nuts that are so tight or rusted? Loosening such nuts and other pieces of metals may be a tall order. However, with the best penetrating oil, this can be achieved with much ease. Penetrating oil, is commonly referred to as rust buster, as it does the job effectively.

The oil has the capacity to penetrate into metal treads and this makes it easier for you to be able to remove your bolts and nuts. Penetrating oil is useful for both residential and industrial functions as they can go through very narrow gaps.

There are so many different brands of the penetrating oils and you may be confused as to which would be the ideal for your needs. In this article, i will look at some of the options that can work effectively.

Now remember one important thing that Penetrating oils can be used on metal, vinyl, wood, rubber, leather and plastic components.



Editor's Rating


Kano Aerokroil Penetrating Oil, 10 oz. aerosol (AEROKROIL)

Kano Kroil Penetrating Oil, 8 oz. liquid (KROIL)

LIQUID WRENCH L106 Penetrating Oil, 5.5 Oz

SiliKroil Penetrating Solvent, 10 oz. aerosol (SILIKROIL)

Castle Thrust Penetrating Oil, 15.75 oz

What is Penetrating Oil, Exactly? 

You may be shocked to realize that you may have come across or even used penetrating oils, but did not know what it was. There are many lubricants that perform similar functions and as such it may be hard for an average person to tell apart.

Well, penetrating oils are liquids, which are known to have a very low viscosity. As such, the oil flows easily and is commonly used to loosen parts that are stuck together and have rusted. One of the key abilities that this solvent has, is being able to penetrate through very narrow gaps. When you apply the oil, it leaves a film on the surfaces and this will loosen the parts.

Why You Need Penetrating Oil?

When searching for the penetrating oil, it is imperative for you to understand the specific uses. As mentioned earlier, the oil is mainly used for loosening nuts and bolts that have rusted together. However, there are other purposes that it can be used for like protecting mechanical parts from corrosion and even lubricating some parts. Ideally, this serves three main purposes; moisture displacement, protection and lubrication.

Using high quality penetrating oil should also provide resistance from the elements that may cause rust and corrosion.

Some of the parts that penetrating oils can be used on, include:

  • Suspensions
  • Bushes
  • Hinges
  • Air tools
  • Bushings
  • Casters
  • Chains
  • Cables
  • Electrical terminals
  • Gear and so many more

The key thing is to find the most suitable penetrating oil for the specific use. And be with me, that’s what I am heading to and will show you some of the suitable product reviews, so you can choose the right one for you around the market.

Our Best Penetrating Oils Reviews:

The market is flooded with so many different types of penetrating oils. But among them i have picked some of the top rated brands for you, and i hope that this would be useful in your search for high quality penetrating oils.

1. Kano Aerokroil Penetrating Oil, 10 oz. aerosol (AEROKROIL):

This penetrating oil by Kano is known for its ability to creep through tiny spaces and loosen frozen metals. It is quite effective in that it will reduce the surface tension between parts. Do you know that it can go through spaces that are as small as one millionth of an inch? Kano Aerokroil is formulated as the aerosol of Kroil and this is why it will loosen any frozen metal parts pretty fast.

In addition, this solvent has the capacity to dissolve oil, dried grease and gum, without damaging the metal. It will displace moisture and prevent rust on metal parts. It is an effective lubrication for chains, nuts and bolts.

The mechanical parts that are stuck together will be freed and there will be no reaction between the solvent and the metal. While it has all these capabilities, it is quite affordable and as such, should be considered.

Highlighted Features:

  • check
    A durable lubrication
  • check
    Aerosol version of Kroil
  • check
    Prevents rust and corrosion
  • check
    Same level of service and reliability
  • check
    Penetrates spaces that are really as tiny
  • check
    Affects in just a couple of minutes
  • check
    Dissolves dried gum, grease and oil
  • check
    Does not reacting with the metal
  • check
    Industry approved penetrating oil
  • check
    Can be used for various purposes

2. Kano Kroil Penetrating Oil, 8 oz. liquid (KROIL):

Kano Kroil has a great reputation of being able to penetrate through frozen metal joints and loosen them in a short while. This is quite convenient as it will creep through the threads of frozen and even rusted metal parts. 

This penetrating oil is known to be multipurpose as you can use it as a lubricant and also prevents rust and corrosion. In most cases, such strong lubricants have side effects, but Kroil will loosen the parts, without damaging the metal or causing any reaction.

If the joints have moisture or water, the oil will displace them and reduce the surface tension. Penetrating through one millionth of an inch makes this oil ideal, even for joints that are tightly stuck. This makes the process of removing and replacing rusted and frozen components much easier.

It will also dissolve dry gum, oil or grease from the metal parts easily, without affecting the metal. Sold in an 8 oz can, this is one of the most affordable, yet effective penetrating fluids.

Highlighted Features:

  • check
    Loosens frozen joints fast
  • check
    Penetrate through narrow openings
  • check
    Dissolves chewing gum, dried grease or oil
  • check
    Prevents rust and corrosion
  • check
    Reduces the surface tension

3. LIQUID WRENCH L106 Penetrating Oil, 5.5 Oz:

The Liquid Wrench is the best solution for stuck components that need to be replaced or removed. This has become a trusted brand of penetrating liquid and is ideal for tough applications. The anti-seize formula helps it to act quite fast to loosen the stuck nuts and bolts. 

The Liquid Wrench will cut through oil or grease and will also dissolve rust. This is attributable to the low viscosity. It is known to have a low surface tension and high levels of lubricity and solvency.

Where there are extremely tight threads, this would be the most suitable oil. It can creep in right though tiny spaces and stop corrosion, and help loosen stuck parts. Liquid Wrench has been in existence for over 7 decades and is known to have consistent and superior performance. If you have any frozen mechanisms, use this penetrating oil to loosen and free them.

Highlighted Features:

  • check
    Multipurpose penetrat
  • check
    Can be used for various applications
  • check
    Cuts through grease
  • check
    Dissolves rust and corrosion
  • check
    It aerosol in this penetrating liquid
  • check
    Fast penetrating and will loosen nuts and bolts fast
  • check
    Has anti-seize properties
  • check
    Low odor and is safe to use on plastic
  • check
    Also can be used on painted surfaces as well as PVC

4. SiliKroil Penetrating Solvent, 10 oz. aerosol (SILIKROIL):

SiliKroil is also known for its ability to penetrate through very tiny openings. With this oil, you will be able to loosen and disassemble any mechanical components that may be stuck up together due to rust. The special formulation will dissolve all the iron oxide granules that cause rust on the metallic components. 

When this happens, the joints are freed up and it becomes easier to remove or replace them. The other advantage with the penetrating oil from Kano is that it will also serve as a lubricant.

When you apply this oil to metallic parts, it will prevent rusting and has the capacity to resist wetting and moisture. This is ideal for heavy manufacturing applications and has an advantage of being multipurpose.

The lubricant and penetrant properties make this to be a suitable choice for various applications. For the industrial machines that perform several tasks, you should use this penetrating oil as it will distribute the load evenly and reduce wear and tear.

Highlighted Features:

  • check
    Creeps through extremely narrow gaps
  • check
    Has both lubricating and penetrant properties
  • check
    Breaks down iron oxide particles that cause rusting
  • check
    Resists wetness, moisture and corrosion due to its lubricity
  • check
    Reduces surface tension to react effectively
  • check
    Penetrating through stuck joints is easy

5. Castle Thrust Penetrating Oil, 15.75 oz:

The manufacturer of Castle Thrust Penetrating oil has discovered a unique formula that is ion activated. As such, it will penetrate and serve the purpose without burning off. It takes effect fast and the unique formula will also ensure that the components are not damaged. 

It can penetrate through small spaces to be able to loosen nuts and bolts that are hard to loosen. It comes with high temperature resistance and once it is applied, it will foam and creep into the threads, without running off the metal surface.

Upon using it, this serves as a great lubricant and as such, when it gets to the surface, it will play a critical role in preventing rust and corrosion. The superior affinity for metal is what makes this penetrating oil give a powerful performance.

The good news is that it is quite affordable and you can easily purchase. The only drawback is that it seems to have a very strong odor compared to other penetrating oils.

Highlighted Features:

  • check
    Super affinity to metal
  • check
    Unique ion activated formula
  • check
    Superior temperature resistance
  • check
    It penetrates safely, without burning off
  • check
    It foams around the metal without running off
  • check
    Great lubricant to protect parts from rust and reduce friction

6. Loctite 37585 Penetrating Oil, 12 oz:

Powerful penetrating oil with the ability to cut through and dissolve dirt, oil and rust.Use it to loosen pipes, studs, nuts and bolts fast and easy. When the Loctite LB is applied, it will get rid of the frozen joints and then serves as a lubricant on the surface that it has been applied on. 

This means that you will not have to worry about further rusting and corrosion. Inasmuch as Loctite penetrating oil is powerful, it is safe to the ozone layer as it does not contain harmful compounds.

This isversatile penetrating oil for youthat can be used for the assembly and dismounting of machines and other components. It will seep into tiny spaces and threads quite fast and starts working right away.

When the rust and dirt is removed, there is an oily coating that will remain on the surface as a lubricant. This will also dispel moisture and water and thereby prevents rusting. It is will reduce friction and facilitate smooth movement of the metallic parts.

Highlighted Features:

  • check
    Versatile penetrating oil
  • check
    Resists water and moisture
  • check
    Can be used on a wide range of applications
  • check
    Penetrate into pores and cracks fast and easy
  • check
    Lubricant that leaves an oily coating on the surface
  • check
    Contains no toxic compounds that are known to deplete the ozone layer

7. 3-IN-ONE 10038 Multi-Purpose Oil 8 oz (Pack of 1):


To loosen frozen parts, reduce friction and get rid of rusty joints, consider this penetrating oil. As the name implies, this is a multipurpose penetrating oil, which can be used for various applications. You can use this oil to remove gum, grease and even silence components that have squeaky noises. 

The drip application and a squeeze bottle are part of the unique design of the package. This is meant to give you absolute control during the application process and avoid spills.

Even if the parts that have been stuck together for a long time, this penetrant has the capacity to loosen them. It will seep into crevices and free the stuck parts in a matter of minutes. For cleaning purposes, this penetrating oilis useful as it removes dirt and grime effortlessly. It will work as a lubricant and does not any odor or foul smell.

Highlighted Features:

  • check
    Great lubricant to reduce friction
  • check
    It acts with speed to loosen parts
  • check
    It is odorless and has no unusual smell
  • check
    It has a squeeze bottle and a drip applicator
  • check
    Will give you great control while you apply
  • check
    Powerful penetrant that will creep into crevices
  • check
    Multipurpose penetrating oil and quite effective

8. CRC Knock'er Loose Penetrating Solvent, 13 oz Aerosol Can, Reddish:

The CRC Knock’er lives up to its name as it has great penetrating abilities. Sold in a 13 oz aerosol can, this is an ideal solvent for disassembly of mechanical parts that need maintenance or replacement. The oil flow into crevices, cracks, joints and threads of stuck parts. It works on tools and machinery as well. 

There is an advantage of using this penetrating oil as it does not contain VOCs, which are harmful to the environment. Once you apply it, it will leave a lubricant coating on the surface to prevent rusting.

This solvent comes with industrial strength and has a very low viscosity. The low surface tension formula will allow it to penetrate into very tiny spaces to dissolve grease, gun, oil and corrosion. It is very easy to use as you can spray it from any position, to get it to the targeted surface. This is made possible by the 360 degree valve.

Highlighted Features: 

  • check
    Allows it to creep into tiny spaces
  • check
    The special low surface tension formula
  • check
    Leaves behind a lubricant coat on the metal
  • check
    Does not contain any volatile organic compounds
  • check
    Eases your assembly and disassembly of tools, equipment and machinery

What to Look before Buying Penetrating Oil?

The market is flooded with tons of brands, with each one claiming to be the best penetrating oil. Obviously, this can be quite confusing for you, as you may not know what to look for. In this section, we will look at some of the key factors that can help you to find the most suitable penetrating oil based on some purposive criteria’s.

Penetrating oils have the same functionality as other oils and lubricants. However, there are specific attributes that will make the penetrating oil unique and useful for your purpose.

The main objective of using penetrating oils is to be able to loosen stuck components, especially metal. In most cases, these will be metallic parts that have rusted, making it hard for them to be freed.

With this in mind, it means that the surface is usually damaged and forcing to loosen them will only make it worse. The penetrating oil will get rid of the rust and dirt without exposing the metal parts to any danger.

Here are some of the key considerations to bear in mind whenyou are shopping for penetrating oil:

Low Viscosity

From the definition, the low viscosity is the main characteristic of penetrating oil. This is what allows them to have a low surface tension and be able to seep through tiny spaces. You should look for a brand that has a low viscosity so that it can work effectively. Using oils with high viscosity will end up causing more damage to the stuck components and they will remain stuck.


To prevent such case of having the metal parts stuck in the future, you will need penetrating oil that has great lubricating capabilities. As soon as the oil penetrates into the thread and removes the rust, it should leave a lubricant film, which will prevent future rusting and corrosion. As such, you need to look for a penetratingoil that has multiple uses.

Ease of Use

You should find a solvent that is easy to use and apply. You will want to buy penetrating oil that can be applied at any angle without too much strain. There are some options that need to be mixed with other additives, which may complicate the whole process. It is advisable to buy penetrating oil that is ready to use.

Environment Friendly

There are manufacturers who are keen on the environment and as such, they will formulate penetrating oil that does not have ozone depleting compounds. It is also ideal for youto go for the penetrating oils that have no odor, which makes it easier to use it even inside your home.


The price factor is also an essential consideration. Look at the different brands that are offered within a particular price range and compare their features. Always go for one that gives you value for the money. However, it is not logical to compromise efficiency for a lower price.

With these few pointers, one should be able to sift through the various penetrating oils on the market and pick the suitable one. Expert reviews also serve as a good guide to the most effective penetrating oil.

Uses of Penetrating Oil

Generally, penetrating oils are effective in loosening frozen nuts and bolts. However, there are so many other applications that they can be used for. Let us look at some of the other uses of penetrating oils that would serve your needs:


Besides penetrating and loosening the stuck components, penetrating oils are effective lubricants. Once applied, they will have a lubricant film that will facilitate smooth movement of the parts and reduce friction.


The other significant use of the penetrating oils is that they will serve as anti-rust agents. They have the capacity to dispel water and moisture and as such, the parts will not rust or get corroded. This means that you can use penetrating oilfor routine maintenance to prevent rusting and corrosion.

Cleaning Agent

Penetrating oils also work as cleaning solvents, and an effective one. They will remove grime, grease, oil, gum and tar among other contaminants. Once you apply the penetrating oil, it will cut through these particles and makes cleaning effortless. The advantage is that it will not affect the surface that is being cleaned.

Multi-Purpose Solvent

Different studies have proved that penetrating oils have quite a number of uses. Besides the ones highlighted above, you can use it for silencing squeaky hinges and suspensions. In cases of sticky residue, penetrating oil will do the work thoroughly. However, when one is not sure, it is advisable to seek guidance as the formulation of the penetrating oil may end up damaging certain surfaces.

The components and active ingredients are almost similar. However, it is advisable for youto look at each product independently so that you can learn in what applications it can be used, without causing any harm.

Types of Penetrating Oil

When searching for the best penetrating oil, it is only logical to note that there are different types of penetrating oils. Each type is unique and will have properties that set it apart from the others. Here are the main types of penetrating oils that you should consider:

1. Straight Penetrating Oils 

These are commonly used in machine operations and will be ready to use, straight from the shop. You should not dilute them when using the. The key ingredients used in making them are base minerals or petroleum products, in addition to polar lubricants like vegetable oils, fasts and esters. There are instances when they have pressure additives like chlorine sulfur and phosphorus.

2. Water Soluble and Emulsion Penetrating Oils 

With these type of penetrating oils, you will notice that they have a very high dilution or low concentration. The water content in these oils are quite high and this is what creates an emulsion when they are mixed with water. You will need to dilute these penetrants before use.

3. Synthetic and Semi-synthetic Oils

Last, but not least, are the semi-synthetic and synthetic penetrating oils. These are usually made up of synthetic compounds. They are usually mixed with synthetic fluids and water. If you are looking for an economical solution, then, this might be the best option for you. They are also known to have a high level of fire resistance.

In your choice of the penetrating oils to use, it is advisable to be sure of the specific type and the properties that it has. This is the only way that you can make the most of the penetrants.

Penetrating Oil vs. WD40

WD40 is a common solvent that is usually in spray form and you can use it in so many cases. What most people do not know is that WD40 is actually a penetrating oil and has the ability to seep through tiny spaces. 

This can be used to break apart parts that are stuck together. It is also a lubricant that will leave a coating on the surface to prevent corrosion and rusting in the future.

WD40 has the ability to drive moisture from any parts and will be useful in so many applications. All the traits that are displayed by WD40 are of penetrating oil and as such, it can be used in the same manner as any other brand of penetrating oil.If you have this penetrating oil, you are safe.

Frequently Asked Questions and Answers

1. How long does it take for the penetrating oil to take effect? 

Ans: While penetrating oils may vary in terms of their properties, most of them should take effect after about 15 minutes. This time may vary depending on the quality of the penetrating oil that you are using.

2. Can I use penetrating oils to prevent corrosion?

Ans: Yes, penetrating oils have anti-corrosion properties. However, this will also depend on the specific one that you have. Some may not have the same ability to prevent rust and corrosion.

3. Do penetrating oils damage plastic components?

Ans: In most cases, the formulation of penetrating oils is made in such a manner that it will not be harmful to plastic parts. However, there are some types of plastic that can be damaged. You should avoid using penetrating oils on polyurethane.

4. Are penetrating oils lubricants or only work to loosen rusted parts that are stuck together? 

Ans: Penetrating oils are very good lubricants. As long as you get quality penetrating oil, it will leave a lubricant film on the surface, which reduced friction and facilitates smooth movement of parts. There are specific ones that come with additives that will be useful for long-term lubrication.

5. Will penetrating oil loosen a frozen water valve? 

Ans: Yes, the penetrating oil should be able to loosen a frozen water valve. You should apply it and leave it for a couple of minutes and the valve should turn easily.

Final Words

In closing remarks, we have tried to discuss as much as we can about penetrating oils. If you have come this far, then there is so much that we have covered. This should be an ideal guide to help you in getting the right penetrating oil. It is essential to be sure of the surface that the penetrating oil is being used on so as to ensure that one gets the right one.

Remember that there are different types of penetrating oils and using the wrong one may end up damaging the surface. I have tried to make the work easier for you by highlighting some of the top rated penetrating oils on the market.

While we may not be able to handpick the best penetrating oil, we believe that any of the products we have reviewed should serve the purpose. You should strive to pick high-quality penetrating oils and this will serve the purpose.

Follow this guide and the process of buying the ideal penetrating oil will be much easier. It is our sincere hope that this guide will be useful for you and we will keep updating it, with the entry of new penetrating oils.

Charles Thompson

Click Here to Leave a Comment Below 0 comments

Leave a Reply:

%d bloggers like this: