Best Penetrating Oil [The Top Rated, Best Selling Models of 2019]

All of us have encountered that one rusted bolt or seized engine that has been lying around for so long that it is tough to find ways to loosen it and make it work.

This is where penetrating oils can be of great help to anyone – whether they are professionals in the field or just a homeowner.

Penetrating oils are petroleum-based, low-viscosity lubricants that seep into bolt threads and similar tight spaces to lubricate them.

This process helps in loosening the metal parts and facilitates easier movement. If you are confused about what type will work best for you, here is a guide to the best penetrating oils.

What Is a Good Penetrating Oil?

Penetrating oils are not the usual lubricants that you find in hardware stores. What sets these oils apart from regular lubricants is their low viscosity.

Viscosity is the term used to refer to a liquid’s resistance to flow when any force – for example gravity or pressure – is applied to it.

Penetrating oils are a part of a class of petroleum-based lubricants known as thin-film lubricants, whose viscosity is so low that it is similar to that of water.

However, penetrating oils have no other similarity to water and are highly water repellent.

Selecting Penetrating Oil for Rusted Bolts

There are a large number of nuts and bolts that we forget about over a period of time and when we do get back to it, there is a reddish substance that has formed over the metal products, causing them to get stuck.

Once rusted, nuts and bolts are tough to take off, but that is no reason for you to worry. Keep your head straight and don’t try to yank at the bolts in anger as you may make the situation much worse.

Once they are stuck, rusted nuts and bolts can’t simply be cut off and you will need to use some type of liquid tread loosener or penetrating oil to make them come loose.

A number of brands are available in the market so you can simply purchase these to reduce the torque required to overcome any rusty bond.

Just soak the treads of the bolt liberally and let the oil work its magic. It is important to note here that patience is key, as you may have to give the oil some time before its lubricating effect sets in.

Penetrating Oil for Seized Engine

Automobile enthusiasts are always excited at the prospect of coming across a long lost classic car, motorcycle or other pieces of machinery at a great deal.

These old cars, however, may come with their share of problems.

For example, if the car’s engine has been stored in a dry location and checked regularly by being turned over a few times, it can manage to survive for quite a few years.

The problem arises in the other extreme when it has stayed outside for a long time or in damp conditions. In such cases, engines can quickly seize up because of corroded pistons or rusted bores.

In the latter situation, it will not be wise to try to force an engine to start if it has been staying still for a long time. The recommended combination for dealing with seized engines is patience and penetrating oil.

Top 5 Reviews of Penetrating Oil

Best Penetrating Oil In Aerosol Form: Kano Aerokroil

Coming from one of the best companies in the business, this penetrating oil is a great product if you are looking for something that will creep into small openings and reduce the surface tension, loosening the parts that are stuck. This aerosol version of Kroil is available in three different sizes – 10 OZ, 13 OZ and 16.5 OZ.


  • Displaces water
  • Long-lasting lubrication
  • Loosens frozen parts and metal joints
  • Works at a quick pace


  • Good Cleaner: The Kano Aerokroil is a great cleaner that will not only make your old parts work like new, but also make them look like new with just a small manual-cleaning effort.
  • Great Protection: Once you have applied it to the affected area, the oil will give you high quality and long-lasting protection from rust.
  • Good Lubrication: It consists of additives that give good lubrication.
  • Performance: Works quickly within a few minutes to loosen parts that are stuck.


  • Dissolving Effect: The product might not be suitable for use on all types of materials as it could simply dissolve some of them.

Best Option for Complete Gun Care: Gibbs Brand Lubricant

While the Gibbs variant works exceedingly well in most situations, it is the most popular choice in the weapon industry as the brand improves firearm action and preserves pieces regardless of whether they are in or out of use.


  • The complete gun care option
  • Cleans, lubricates and protects for up to 5 years
  • Corrosion inhibitor
  • Water repellent


  • Prevents Oxidation: Even a light coat of the product can minimize the possibility of oxidation.
  • Versatile: Used across the board by military, police, mechanics and body shops.
  • Repels Water Effectively: Water is the biggest enemy of metal products and this penetrating oil helps keep it away.


  • Rust Removal Takes Time: The product doesn’t work very fast and it can take some time to remove rust completely.
  • Most Expensive: It will cost you more than all the other options discussed.

Most Popular in the Market: B’laster – 16-PB-12PK – Penetrating Catalyst

The PB Penetrating Catalyst by B’laster is known for its power when it comes to busting loose frozen or rusted parts, which are a result of corrosion and rust, all in a matter of minutes.

The penetrating oil contains a non-evaporating lubricant that gets the work done fast and also protects the parts against any further corrosion or rust. The spray works very well on rusted nuts and bolts.


  • Breaks free rusted or frozen parts
  • Protects against further rust and corrosion
  • Can be used on automotive, industry, marine and plumbing amongst others


  • Low Surface Tension: Helps the penetrating oil loosen stuck parts with great ease and lubricates them for better function in the future.
  • Works Well for Brakes and Suspension System: The additives in the oil provide for better lubrication that is beneficial for brakes and suspension.
  • Temperature Tolerant: The B’laster penetrating oil is tolerant to high temperatures, even up to 152 degrees Fahrenheit.


  • Hard to Apply: There is no straw provided with the packaging so it can be difficult to apply.

Most Well-known Option: WD-40 Specialist Rust Release Penetrant Spray

The WD40 variant is the most widely known rust-penetrating spray in the market and has been around for decades. This penetrating oil is of superior quality and is known for its structure and formula that is made up of special surfactants, solvents and their signature blue torch technology.


  • Multi-use lubricant smart straw
  • Blue torch technology
  • One formula with five functions
  • Safe formula


  • Safe to Use on a Variety of Mediums: Can be used on plastic, metal, as well as rubber without damaging them.
  • Blue Torch Technology: The company uses this unique technology only for this particular spray that results in a great, highly rated product.
  • Great at Loosening: Even frozen or stuck locks, bolts and nuts can be loosened quickly and with great ease.


  • Strange Smell on Use: The WD-40 penetrant spray emits a slightly strange odor when used.

Best Penetrating Oil for Rusted Bolts: Kano Kroil Penetrating Oil

Kroil is one of the best options available in the market and is known for its capability of penetrating even miniscule spaces. Kroil dissolves and prevents rust from forming without actually attacking the metal.

The penetrating oil displaces water, any dissolved gum, remnants of dried grease and also provides lubrication. It has a unique chemical structure that is engineered chemically for the purpose.


  • Highly water-resistant protective layer
  • Thin, wet film for long-lasting protection and lubrication
  • Reduces surface tension
  • Designed for industrial strength


  • Effective: The results are quick to appear and you will not have to spend more than 15 minutes for the penetrating oil to work.
  • Lightweight: The product is extremely light and compact so you won’t have to worry about carrying it around.
  • Great Rust Prevention: You will not have to worry about rust once you have applied it. Apply it regularly and all your things will remain rust-free.


  • Lubrication: The penetrating oil is only a temporary solution if you are looking to improve lubrication and will not stay there for too long.
  • Tough to use: There is no straw or attachment with the oil so it can be a little inconvenient to use.


The right penetrating oil for you depends on your personal needs. You may want to go with the Gibbs Brand Lubricant if you own weapons and would like to keep them well oiled.

If the rusted nuts and bolts are your area of concern, the Kano Kroil Penetrating Oil may be your best bet. Whichever penetrating oil you choose, be sure to allow it enough time to work its magic on the metal.

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