The Best Penetrating Oils

Posted: October 16, 2019

Anyone who has ever strained their shoulder or scraped their knuckles trying to loosen a stuck bolt knows the value of penetrating oil. In fact, you’ve probably heard the joke about every shop needing at least one roll of duct tape, and one can of a famous, sprayable lubricant.

Penetrating oils can be used to loosen and separate some of the most tightly stuck objects. In fact, nothing works better. How do you find the right oil for your garage or shop?

This review of penetrating oils will detail the features of the best oils, and provide you with the information you need to make the best selection. Be sure to read through to the bottom for some additional information on penetrating oils for home and garage.

10 Best Penetrating Oils For Your Home And Car

1) Kano Kroil

This version of Kroil oil is the original, not the aerosol version that is reviewed below. Kano Kroil has been around for decades, and still comes in a very retro looking oil can. It’s well known for its ability to loosen the tightest, frozen metal parts.

This is an extremely low viscosity oil, meaning that it can get inside small spaces. According to the brand, it can penetrate an opening that is a millionth of an inch. This is a great shop oil if you deal with rusty metals on a regular basis.

This penetrating oil has a spout to assist with application, you can also insert a needle tip for even better precision. Because Kroil oil has such low viscosity, it isn’t very good for lubricating. Still, this is the best oil for penetrating purposes on this list.

Pros & Cons


  • Spout designed for precise application
  • Lasts nearly forever
  • Great for direct application and penetration
  • Good oil at a great price


  • Not a budget priced oil
  • Petroleum based product

2) Castle Thrust C2005

Castle Thrust is an efficient oil that works fast and penetrates well. It’s flagship feature is Thrust. This uses the ability of oil to work well with metals, and loosen stuck pieces quickly. In addition to this, because the oil is low viscosity and foams, it will stay in one area without running and dripping. This is a unique feature when compared to other penetrating oils.

Castle Thrust can work with high temperatures. However, it is still flammable. Users should also know that it is toxic when burned. Spray this oil on any stuck metal, and it should be effective within about three minutes.

Pros And Cons


  • Works for a variety of uses
  • Foams to prevent drips
  • Works at high temperatures
  • Convenient aerosol spray
  • Ion activated works quickly and  gets great results


  • Petroleum based product
  • Flammable and toxic when ignited

3) B’laster 16 PB

We’ve listed two versions of the B’laster penetrating oil. This is the larger size. It’s ideal for commercial shops, or if you decide that this is the ideal oil for your needs. 

This oil is primarily used for penetration and loosening stuck or rusted metal parts. There are some lubricating properties here, but it’s not ideal for that purpose. If you are looking for a lubricating oil, consider something else on this list.

B’laster is one of the more enduring and popular brands on this list. The product has been available since the 1950s, and is quite effective at its job. If you’ve chosen B’laster as your oil, consider this if you prefer a larger container.

Pros & Cons


  • Powerful at unsticking rusted and frozen items
  • Anti corrosive properties
  • Works well for automotive, home, and marine
  • Convenient, larger container


  • Poor choice for lubrication
  • No straw for targeted application
  • Low flashpoint

4) WD-40

It would be difficult to find a more well-known aerosol oil than WD-40. In fact, it’s more likely than not that there’s a can of this stuff in your garage or under your kitchen sink. It is a multipurpose oil that is useful in a variety of household and shop applications.

WD-40 has an interesting history as it was invented by the military for the purpose of cleaning the parts used to make missiles. Now, it is used largely for penetration, freeing stuck fasteners, for lubrication, and to protect metal from rust and corrosion. It can also work to displace moisture.

This is an aerosol product that comes in an 8 oz size. It has a spray head for wider applications, and a smart straw for very precise application.

WD-40 also works well for cleaning. It will dissolve gum, super glue residue, grime, and other corrosion for penetrating rusty screws and other fasteners.

Pros & Cons


  • Spray head or straw for different application options
  • Two way aerosol spray
  • Well known and easy to find product
  • Provides penetration, moisture displacement, lubrication, and anti-corrosive properties


  • Can damage plastic
  • Limited use for lubrication

5) 3 in One 10038

This 3 in one oil is a multi purpose product that has been available for more than 100 years. It can be used as a penetrating oil, to protect tools, and for lubrication.

It comes with a long drip spout to reach into tight spaces. That makes it ideal for working with tools, and for automotive applications.

This is one of the best lubricating oils on this list. Further, the squeeze bottle helps you to control the amount of oil that comes out each time you use it. This product is also idea for helping to loosen stuck bolts.

Finally, this is the least expense product on the list. It is our choice for best budget penetrating oil.

Pros & Cons


  • Excellent lubricating oil
  • Long drip spout to get into tight spots
  • Penetrates quickly
  • Low Price
  • Squeeze bottle for better control


  • Not very viscous and other oils penetrate faster
  • No option for spraying the oil

6) Kano Aerokroil Aerosol

Kano brand’s penetrating Kroil oil is unique because it is the result of a successful lab experiment. The result is an oil that can penetrate an opening that is one millionth of an inch. It is known to be one of the best and most popular penetrating oils there are.

Kano Kroil comes in different packages. This version is Aerokroil. That is the company’s proprietary Kroil oil in an aerosol can. Simply spray the oil directly on the affected parts. A straw is included for applications that require more precision.

The only real negative here is that it is a petroleum based product. There are situations where this is not the worst case.

Pros & Cons


  • Penetrates everywhere with ease
  • Loosens frozen bolts in no time
  • Dissolves without damaging metal
  • Easy to use


  • Petroleum product that is not good for many applications
  • Somewhat more expensive than other options

7) Loctite 503054

This is not one of the better known brands on this list, but the company does produce a wide variety of lubrication and cleaning products. Here, we are reviewing a 12 ounce aerosol spray can. Loctite penetrating oil has been made to loose pipes, bolts, and hinges. It also acts as a protectant. The product does not work well for lubrication.

Not only does this product deal well with ordinary rust, it works with frozen fasteners including valves and bearings. It can dissolve sticky residue as well. The product does not contain any ozone depleting chemicals.

There are some negatives here. There are better priced oils on this list. It is also not a very heat resistant oil. Still, it can work wonders on a seized bolt.

Pros & Cons


  • Great rust fighting properties
  • Quick penetration
  • Works well for a variety of uses
  • Won’t deplete the ozone


  • Pricier than average
  • Not the best penetrating product
  • Extraordinarily flammable

8) Kano Silli

This is another version of Kano Kroil. However, in this case rather than penetration being the focus, it is lubrication. To make this oil, Kano added dimethyl silicones to their original product. This increased its ability to lubricate, and it loosens hinges and other joints that have already been unstuck with a penetrating oil.

Kano Sili offers the best long term lubrication, and also works well for penetration. Silicon is also water repellent. This can prevent rust in the long term. This combination of lubrication, protectant, and penetration makes this product ideal for moving parts.

Pros & Cons


  • Silicon added for better lubrication
  • Water repellent
  • 16 oz aerosol can for long lasting use and easy application
  • Kroil signature penetration power


  • A bit expensive
  • Petroleum Product

9) CRC Knock’er Loose

This is one of the more unique products on this list. It is designed to free loose and frozen parts. It works by employing a fee action system that cracks through rusted surfaces. Then, it penetrates deeper than many other oils.

Knock’er Loose works by freezing the area on which it is applied. This causes cracks in the surface of any blockages allowing the oil to penetrate and begin to work.

Even better, the product is in an aerosol can that can be deployed from any angle, even upside down. The product is VOC compliant and is certified for use in meat processing plants.

Unfortunately, this product is temperature sensitive. You cannot use it on car engines or other high temperature applications because of the risk of fire.

Pros & Cons


  • Aerosol can for easy application
  • Loosens both frozen and rusted parts
  • Proprietary freezing action to quickly break through and penetrate
  • Works on a wide variety of moving parts


  • Other oils have better penetrating properties
  • Very flammable

10) B’laster 8 PB

This is a great, low priced penetrating oil. This 8-PB product is worth a second look.

B’laster PB is known as a true penetrating oil. It quickly enters into the deepest of spaces to get to work on rust, gunk, grime, and frozen bolts. 

In addition to being a penetrating oil, it is also a lubricant. Because it doesn’t evaporate, it helps to keep moving parts working smoothly. It also protects against rust and corrosion.

This oil works very well in industrial or automotive applications. You can obtain it in  multiple sizes including a 5 gallon pail.

Pros & Cons


  • Great lubricant
  • Anti rust and corrosion
  • Works in tight spaces
  • Quick and effective product
  • Budget priced


  • No straw applicator available
  • Low flammable temperature

Penetrating Oil Buyer’s Guide

At first glance, it may not seem as if there are any meaningful differences between different penetrating oils. In reality, the differences may be subtle, but they make different oils better for different jobs.

In the paragraphs below, we’ll go over the points you should consider before determining the best oil for the job. Who knows, you could decide to stock your home or workshop with more than one selection of penetrative oils.

Think of The Jobs You’ll be Doing

Before you do anything else, think about the tasks you perform that might require a penetrating oil. Obviously, these oils are used for loosening bolts, screws, and other metal fasteners. There are other uses as well. These products are used to clean metal, stop rust and corrosion, and as temporary sources of lubrication.

One thing to consider is heat. If you regularly work with heated metals, you need to choose an oil that can withstand that. You’ll also want to consider the other types of materials that could come into contact with your chosen oil. Choose carefully if staining or other damage might be an issue.

Know The Different Types of Penetrating Oil

Every penetrative oil falls into one of three categories. These are emulsion, synthetic, and straight. 

Emulsion – This is a water soluble oil with a large water content. Emulsions usually contain a concentration of under ten percent. They are often used when there is a concern for damage to  materials.

Synthetic – There are synthetic engine oils as well as semi-synthetic. These are made from man made compounds including esters and silicone, and may be mixed with water. These oils are more fire resistant than other oils. They are also pricier.

Straight – These penetrating oils are made from base minerals and petroleum based oils. They are used as is, and are not usually diluted. These oils are commonly used where thicker, enduring oils are needed. This includes moving machine parts. Additional lubricants such as fats or vegetable oils are often included in the formula.

The Price of Your Oil

As with anything else in your shop, there’s a good chance that spending a bit more money will help ensure a better product. However, that isn’t always the case. While manufacturers that use the best ingredients generally charge more, you have to consider your purpose. If your oil is only used for the occasional odd job, there’s no real need to invest much money in the product.

How Can Your Oil Handle Temperature

If you frequently work with hot metals, you need to be concerned with temperature tolerance. In this case, you should probably consider synthetic or semi-synthetic penetrating oils.

Choosing an Eco-Friendly Oil

It isn’t  just morally correct to be eco friendly. In some cases, regulations may require you to use lubricants in a way that is environmentally responsible. You might consider choosing a penetrating oil that is as environmentally friendly as possible. Even better if you have customers, and can let them know that you’ve made this decision to go ‘green’.

Viscosity & Lubricity

If your oil is highly viscous, that means it is thicker and won’t be able to penetrate as well. Low viscosity oils, on the other hand, are thinner. So, low viscosity oils are more penetrating. This means they are better at jobs where they must work their way into small spaces to do their job.

Final Thoughts

Now you know the best brands of oils, and what to consider before making your decision. Before you purchase an oil, refer back to this list, and consider choosing one of our top ten selections. As long as you pick the best oil for your needs, you should be happy with your final choice.