5 Best Penetrating Oil for Stuck Spark Plugs: Which One Works Best?

Best Penetrating Oil for Stuck Spark Plugs

Is a spark plug in your car’s engine proving difficult to remove? Without a doubt, you are not the only one who feels this way. Spark plugs often become seized in the engine, making removal difficult from corrosion, carbon buildup, or other factors. It is possible to loosen the plug and remove it with penetrating oil.

 Penetrating oils prevent wear and corrosion by penetrating the tiniest spaces between metal parts. They can also dissolve rust and other deposits, simplifying the spark plug removal process. However, not all penetrating oils are created equal, and figuring out which one is ideal for your needs can be challenging.

In this article, I’ll review the 5 Best Penetrating Oil for Stuck Spark Plugs and what makes them stand out from competing products. The benefits and drawbacks of each oil are laid forth for your perusal. Included as well, for your convenience, is a Buyer’s Guide.

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What Factors should you look into before choosing a penetration oil?

While struggling with nuts/bolts/spark plugs, penetrating oil can be your savior. As many penetration oils are available in the market, sometimes finding the best penetrating oil for stuck spark plugs becomes challenging. Therefore, before buying penetration oil for stuck spark plugs, you must consider some factors.

1. Compatibility to requirements 

Depending on the type, every oil is unique in its features. Therefore, you need to determine which oil type will match your purpose best. If you aim to move stuck spark plugs of the engine, you must pick an oil that can penetrate easily. Therefore, most thin oils will get priority. With thin penetrating oil, you can fix your stuck spark plugs properly. 

2. Quality

To ensure oil quality, you must consider some factors, such as ingredients, viscosity, and oil lubrication ability.

  • Ingredients: Usually, the best penetrating oil ingredients comprise refrigerants mostly than solvents. The refrigerants absorb heat, lubricate properly and make it easier to move the spark plug. Though these oils are more costly than solvent-based ones, they serve far better without damaging the non-metallic parts of your engine, such as rubber belts.
  • Concentration: Moreover, penetrating oil also features high concentration. A penetration oil with high concentration offers faster and more efficient service.
  • Viscosity: Another thing that you need to consider is the viscosity of oil. A lower-viscosity oil will offer a much faster job. Usually, the average viscosity range of the best lubricant oil is about (135-220) SSU.

3. Easy to apply

In this regard, low-viscosity oil can help you. Penetrating oils with low viscosity are easy to apply in stuck spark plugs. They can smoothly access most of the area of a spark plug. So, I recommend you choose low-viscosity penetration oil to penetrate the entire part of the spark plug properly. Thus you’ll be able to remove the stuck spark plug easily. 

4. Price

Price is a crucial factor that usually influences our decision. We all want to get the best one for our budget. Therefore, you need to compare the quality with the cost. If the service you get from the oil is better and saves your engine parts from damage, a little bit of costly oil can be cost-effective in such cases.

For example, refrigerants are costly compared to usual solvent-based penetrating oil but save your car from damage and offer excellent service.

So, comparing the features and prices is wise to get a proper and effective penetration oil for your budget. 

5. Shelf life

Check the manufacturing and expiry date before picking oil. Usually, a perfectly stored penetrated oil stay in good condition for 5 years. But newer oil offers more effectiveness than older one. In addition, the effectiveness and service life of a penetration oil mainly depends on the quality and viscosity of the oil indeed.

How to Remove Spark Plugs That Are Stuck

A spark plug can get stuck for many reasons, such as misfiring, fouling, and corrosion. Among them, fouling is the most common, which usually occurs when carbon deposits hype on the plug’s electrodes. And thus, your spark plug loses its efficiency.

However, you can follow the steps given below to remove stuck spark plugs. They are: 

Step-1: Trace the plugs

Based on your vehicle model, find the spark plug’s location. You may find front sparkers easily, but rear plugs are hard to locate. Many cars can have these plugs under part.

In addition, you can get the rear spark plug visually, but in some cars, you may need to remove some components like electrical connectors or wipers to get the spark plug.

Step-2: Apply penetrating oil

You can apply penetrating oil on the spark plug area; it will loosen the plug and reduce rust/corrosion. Thus, your spark will come out smoothly.

However, you can also use WD-40 oil as penetrating oil. Though this oil isn’t a true penetrating oil, it can aid in reducing corrosion. Just apply the oil and leave it overnight. In some cases, 30 minutes is enough yet.  

Step-3: Tighten the plugs 

This step may sound weird, but tightening is an excellent way to penetrate the oil into the threads. In this case, you can use a spark plug socket wrench to tighten them.

Step-4: Repeat Step 3

Tighten the spark plugs with the wrench and drop some penetrating oil. Then repeat the cycle until the plugs get stuck properly. To do this more ideally, you can start your engine. The engine’s heat will help the spark plugs to expand more widely.

Step-5: Remove the spark plugs

After ensuring the plugs are appropriately tightened, let your engine cool down and then take at least a 6 inches wrench extension to remove the spark plugs.

Recommendation: don’t perform this step while the engine is hot. Otherwise, it may burn your hand, including sticking your spark more tightly. And at this situation, overpressure can tear off the threads of the sparking plug.

Step-6: Clean the plugs

After removing the plugs, clean them with sandpaper or a wire brush. You can also use vinegar or petrol to clean it. Then, soak them in the solution for some seconds, and wipe and dry them. Moreover, you can also try compressed air to clean spark plugs.

Step-7: Install new plugs

Cleaning the plugs and using them repeatedly isn’t workable every time. If the fouled issue is too much, cleaning can’t fix it. In this case, you may need to replace them with new ones. For installing new spark plugs, you must lubricate and clean the ports first, along with removing rust/deposits.

5 Best Penetrating Oil for Stuck Spark Plugs

Quick links

  1. Kano Kroil Penetrating Oil
  2. Free All Deep Penetrating Oil 
  3. B’laster 16-PB Penetrating Catalyst
  4. Liquid Wrench L106 Penetrating Oil
  5. Gibbs Brand Lubricant

Unbiased Discursion About Best Penetrating Oil for Stuck Spark Plugs

1. Kano Kroil Penetrating Oil

Looking for a way to free up rusty and corroded parts and unstick spark plugs? Here, the best option is Kano Kroil Penetrating Oil

Whether you’re working on a car, a motorcycle, or any other machinery, this oil will make short work of any maintenance chore.

If I highlight its superiority against corrosion, I would be hard-pressed to find an equal. Cutting through rust and corrosion makes it useful for free nuts and bolts stuck. That is to say, if a spark plug becomes stuck, you won’t have any trouble extracting it.

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In addition to its defensive properties, Kroil also has a very short activation time. It is superior to competing goods in its ability to quickly and deeply infiltrate hard-to-reach areas. This guarantees that it can access all areas of your engine, no matter how inaccessible, simplifying removing stuck spark plugs and other parts.

Unlike other penetrating oils that can attack metal and leave it vulnerable to further corrosion, Kroil is designed to remove rust and carbon deposits without attacking the metal itself. This means it can leave a long-lasting protective layer, preventing further corrosion and maintaining your parts’ smooth operation.

 What we like? 

  • Helpful in loosening any rusted threads or components 
  • This oil is a potent corrosion inhibitor. 
  • Rapidly and profoundly penetrating
  • It can be used without fear and will not corrode or harm the metal.

What we don’t like?

  • It failed to work on a seized water hose fitting.


Its unique formula and quick-acting properties might help you handle challenging maintenance tasks. Therefore, Kroil should be considered for mechanical component rust and corrosion removal.

2. Free All Deep Penetrating Oil 

Will it be best to combat frozen parts if penetrating oil and potent solvents are used together? Guess what? It is Free of All Deep Penetrating Oil

Concerned with corrosion and rust! 

This oil’s rust-eating chemical component can get to the bottom of corroded metal and dissolve it. Ensuring the penetrating oil has softened the corroded metal means you may loosen the fastened pieces with less spray, torque, and time. This specialized rust eater works well in various industrial settings, including plumbing, automotive, marine, and more.

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The superior lubricant quality of this oil makes it the top pick as a penetrating oil for spark plugs. Unlike its competitors, Free All has a far higher concentration of lubricant so that more of the loosening agent will contact the rusty, frozen portions.

And there’s more!

This “seeking agent” oil, due to its low viscosity and slow evaporation rate, can transport lubricant over greater distances and at a faster rate than conventional solvents. This means a new lubricant will arrive before the solvent is completely gone.

What we like?

  • Instantly removes rust, scaling, and corrosion!
  • Specially designed rust-eating agent loosens red and white lead, tar, grease, carbon, and graphite deposits.
  • Ideal for plumbing, automotive, marine, and industrial applications.
  • It’s silicone-free and safe for paint and shop settings.

What we don’t like?

  • If the area is not ventilated, it will not work well.


This non-corrosive Free All Oil is appropriate for use on various surfaces, including metals, plastics, and rubber. The device’s adaptability stems largely from its wide variety of possible applications. Because it includes no silicones, it is also safe for use in paint and shop environments.

3. B’laster 16-PB Penetrating Catalyst

It can be difficult to determine which product has true “lifesaver” qualities when removing rusty or frozen components. Use B’laster 16-PB Penetrating Catalyst, and you won’t have any issues whatsoever.


Its capillary action allows it to penetrate deeply into fissures and cracks, covering every last bit of corroded or frozen surface area. The fact that this catalyst doesn’t evaporate means more time and less stuff saved. Working on a car engine requires the ability to remove rusty nuts and bolts, and this tool makes it simple to do so. In addition, the lubricant safeguards the surrounding components from damage while removing the clogged spark plug.

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 In addition to thawing out frozen or corroded parts, the PB B’laster Penetrating Catalyst can prevent further rust and corrosion. This means that once the blocked spark plug has been removed, you can apply the penetrating oil to the threads to protect them and avoid future problems.

It’s versatile.

You can use the PB B’laster Penetrating Catalyst on many materials and parts. It can be applied to various things, including ships, tools, sporting equipment, ships’ equipment, fishing reels and tackle, and automotive parts. Again, because of its adaptability, it can be adopted in many places, including the house and the workshop.

What we like?

  • It has non-evaporating lubricants
  • Defends against additional corrosion and rust
  • Remove rusty screws and frozen bolts easily.
  • Useful for vehicles, factories, ships, waterworks, and more

What we don’t Like?

  • Smell bad.


The PB B’laster Penetrating Catalyst is a highly useful addition to all kinds of work because it can change into a lubricating layer after being utilized as a penetrating catalyst.

4. Liquid Wrench L106 Penetrating Oil

Fast-acting and anti-seize components make this item one of the best penetrating oil for stuck spark plugs. The anti-seize chemical instantly loosens corroded fasteners and hardware by dissolving the corrosion.

Here’s more!

This oil’s strong lubricity, high solvency, and low viscosity make it ideal for use on even the toughest rust. This powerful mixture can remove rust and cut through grease, making it ideal for rusty nuts, bolts, hinges, clamps, pipe fittings, locks, latches, frozen mechanisms, nozzles, stuck spark plugs, and hose pipe fittings.

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What sets Liquid Wrench L106 Penetrating Oil apart from other penetrating oils?

It’s Cerflon technology. Cerflon, a ceramic-reinforced fluoropolymer, is incredibly wear-resistant and lubricious. Because of this, Liquid Wrench Penetrating Oil will not only help free frozen components but also reduce the likelihood of those components deteriorating and seizing up again.

In addition to loosening stuck spark plugs, this oil is useful for loosening corroded bolts, locks, and other mechanical components.

What we like? 

  • Effectively eliminates rust and liquefies grease due to its potent composition.
  • It is safe to use on the painted surface 
  • Comes with low odor 
  • Solid lubricant for maximum protection 

What we don’t like? 

  • It’s a little slippery. 


If you work with fasteners like nuts and bolts, you need Liquid Wrench L106 Penetrating Oil. Strong enough to remove even the most persistent rust, this mixture easily frees trapped spark plugs and other parts.

5. Gibbs Brand Lubricant

Is there anything better than a product that will protect your metal from rust and corrosion while keeping out moisture and other impurities? Yes, I am talking about Gibbs Brand Lubricant. 

The lubricant’s water-repellent characteristics are what make this lubricant apart. Having this property means that no metals will rust or corrode and that electrical connections will not oxidize from exposure to moisture. For this reason, it is perfect for usage in severe conditions, such as marine and outdoor settings, 

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What’s for stuck spark plugs?

Spark plugs that aren’t replaced regularly might get stuck and be a pain to remove. Here Gibbs Brand Lubricant can do the trick. Because of its penetrating nature can dissolve the rust and corrosion that have clogged the spark plug. As a result, the spark plug can be removed with less risk of damaging the motor.


GIBBS is the only substance on the market that works to neutralize oxidation and undercoat metal so that it can be painted over. When applied to unfinished metal, GIBBS makes it possible for even the dirtiest of hands to handle the material without leaving any markings.

If I describe its safety, Amazingly! The anti-rust and anti-corrosion properties of Gibbs Brand products are meant to last for up to five years. This makes it a good choice for use on cars, machinery, and farm equipment that frequently encounters wet conditions. It can be utilized in both terrestrial and marine settings due to its corrosion inhibitor.

What we like? 

  • It can be used for a variety of purposes
  • Water-repellent properties keep out moisture and protect metals from oxidation near electrical connections.
  • Useful for giving antique machines and automobiles a new lease on life.
  • Useable even in the harshest of climates.

What we don’t like? 

  • Doesn’t perform well on plastics and rubber.


Gibbs is a must for any technician or DIY enthusiast because of its capacity to revert and eradicate corrosion, making it appropriate for use on blocked spark plugs.


  • Can you use vinegar to clean spark plugs?

Yes, you can use vinegar to clean spark plugs. To eliminate carbon deposits:

  1. Take a wire brush.
  2. For better cleaning, soak it in vinegar solution for a few while.
  3. Wipe, and you will get clean spark plugs.
  4. Don’t rub too much or soak in vinegar for longer to avoid damage.
  • How to Remove Stuck Spark Plug From Aluminum Head?

The below tips will help to remove the stuck spark plug from the Aluminum head:

  • You can use a Socket wrench or other tool for help.
  • You can try duct tape also with plug wire remover
  • Use penetrating oil or other lubricant to remove it.
  • To eradicate over-torqued spark plugs, turn the plug reversely.
  • Is it better to remove spark plugs hot or cold?

Never do this when the engine, including spark plugs, is hot. When the engine is heated, it will damage the thread and hole. If your engine’s spark plugs have an aluminum head, this process will expand the hole and thread. Thus, it will be stuck more tightly. So after cooling down, you have to remove the plug.

  • Does oil damage spark plugs?

Yes, oil on spark plugs creates huge issues. They prevent plugs from sparking and disturb the engine from starting. At last, a misfire can occur. For many reasons, such as engine gasket fault can cause oil to leach into spark plugs. You need to find out the reason and fix it soon. Also, clean the spark plugs.

  • What tool do I need to remove spark plugs?

To remove the spark plug socket, the tools you need are:

  • A spark plug extension
  • A feeler gauge
  • Anti-seize lubricant
  • A torque wrench
  • Rubber hose/gloves to overcome engine dirt and hold a good grip.
  • A ratchet wrench
  • Needle-nose spark plug pliers

Final Verdict

You can get back on the road in no time at all if you have the correct penetrating oil to remove a clogged spark plug. The ability to enter small spaces, such as those in a spark plug, is a crucial function of penetrating oil. Both the oil’s drying time and its viscosity, which affects its ability to flow into small areas, impact its effectiveness. 

I hope the information above will assist you in selecting the best penetrating oil stuck plugs. Based on my research, I recommend the B’laster 16-PB Penetrating Catalyst. Its adaptability and ability to rapidly defrost frozen or corroded components make it the best option.

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