The best penetrating oil for stuck spark plugs is one that effectively loosens rust and corrosion without damaging the surrounding components. Products like PB Blaster and Liquid Wrench are popular choices for their ability to break down stubborn debris and make spark plug removal easier.
One of the most annoying things a car enthusiast or DIY mechanic has to deal with is how to remove a stuck a spark plug without causing major damage to the cylinder head or the plug itself. Unfortunately, vehicle maintenance can sometimes reveal stuck spark plugs due to rust, corrosion, or heavy carbon deposits. The right solution is a penetrating oil for stuck spark plugs.
Penetrating oil does wonders to assist with the removal of stuck spark plugs by eating away at the rust corrosion, and rust holding them in place. However, with so many options, it’s usually difficult to select the right one that will actually remove rust without also damaging the threads holding the spark plug or the cylinder head.
In this post, we will walk you through the process of choosing a penetrating oil for stuck spark plugs and how to use it, as well as the best options available.
Contents
What does Penetrating Oil do?
Sparks plugs and other components are sometimes really difficult to remove due to boding with other components or due to inherit rust and corrosion. Regular oils do not breakdown corrosion, rust, or other deposits like pulling moisture from plugs and grains with inner corrosion that is very difficult to outline and shape.
Oil that is oleic and disperses like penetrating oil is very effective and softening and breaking these bonds due to the oils ability to soothe and soften siege material. It traps moisture and combats formation of seizure due to the corrosion of surrounding plugs.
Assessing Why Some Penetrating Oil Works Best For Stuck Spark Plugs
The Most effective penetrating oil for stuck spark plugs should have some attributes that makes it best for breaking apart rusted and stuck components. Among the available products in the market, some oils can
Access tight spaces: Some oils are thin and light enough to access the bottom threads of the spark plug and the bond that is holding it in place.
Decompose rust and oxidation: Some oils have the competency to dissolve rust and the oxidation that is caused on stuck spark plugs.
Lubricate: After the oxidation decomposition, some oils are capable to grease the bottom threads to facilitate an easier extraction of the spark plugs without damaging the surrounding area.
Corrosion: The best oils that allow you to remove the plug will also leave a protective layer for dry rusting and oxidation.
Key Factors to Consider When Choosing the Best Penetrating Oil for Stuck Spark Plugs
Here are some important factors you should consider before choosing penetrating oil –
Penetration & Viscosity
No one wants to deal with stuck spark plugs if they can help it. However, if it comes to that, its best to use effective penetrating oil that is low in viscosity, so it can slip through tight spaces to break the rust. Rust is the residue that bonds the spark plug to the engine, and must be removed for the plug to be removed. Oil that is labeled as penetrating oil is preferred over normal oil, as it’s formulation is better able to handle the demands of tight spaces like spark plug wells.
Ability to Dissolve Corrosion
Typically spark plugs get stuck in the cylinder head because of rust and oxidation that seals the plug. Penetrating oils are best if they contain effective ingredients, like kerosene for dissolving rust, or acids that are able to breakdown the carbon that builds up around the plug. Some oils even contain rust inhibitors to aid in oil the plug to prevent the plug from becoming stuck in the future.
Temperature Resistance & Compatibility with Materials
While the engine is running, the spark plugs can get extremely hot, hot enough for the penetrating oil to need to hold up under heat. The best spark plug oils for removing stuck spark plugs have heat resistance, evaportive resistance, and heat breakdown resistance. These oils should still work well mechnically and not get destroyed to heat at higher temperatures.
It is also important for these oils not to interact badly with the spark plugs or with the components located around the vehicle’s spark plugs. Some penetrating oils with low oxidization resistances will damage the spark plug’s paint, rubbers, and engine plastics. Therefore, the best penetrating oil is also the best oil for the engine and vehicle to not get damaged.
Residual Lubrication & Protection
After loosening the spark plug for the first time, you want to make sure you do not have to go through the same tough process when you want to remove the spark plug next time. Some penetrating oils do. The best penetrating oil will leave a thin waterproof coating that prevents rust and corrosion from forming once the spark plug is protected. This is protective, so that spark plug can be more easily removed next use.
Step-by-Step Guide on How to Use Penetrating Oil on Stuck Spark Plugs
Using penetrating oil requires some patience and care. Here’s a simple guide for those not very experienced.
Step 1: Check That the Engine is Cold
The first thing to do is to make sure that the engine is cold. If you try to take out a spark plug from a running engine, you might burn yourself or damage the threads and the spark plug. Let at least 30 minutes go by after the engine has been turned off before starting the process.
Step 2: Disconnect Battery
For your safety, disconnect the battery’s negative terminal. This precaution will eliminate the possibility of an electrical short, while also preventing sparks from igniting the oil or any other flammable materials.
Step 3: Spark Plug Area Cleaning
Before applying the penetrating oil, you need to clean the area surrounding the spark plug. This is to take out any dirt, grime, or other debris, so that they won’t fall into the engine when you take out the spark plug. Use a soft bristle brush to wipe the area clean or a cloth to finish off the cleaning.
Step 4: Apply the Penetrating Oil
Make sure to put penetrating oil around the spark plug, focusing on the threads that connect to the cylinder head. That isn’t the only part you need to oil; you should put oil on the entire spark plug. Penetrating oil should have a straw that lets you apply it to specific areas. Give it around 15 to 30 minutes to soak in. For plug that tend to be more difficult to get out, let the penetrating oil soak in for the entire night.
Step 5: Gently Loosen the Plug
To begin, you need to get the plug loose in a timely manner. To do this, you need to have a spark plug socket with an extension bar to loosen it. Make sure you don’t apply too much counterclockwise pressure on the plug. You need to loosen a plug without loosening it too much. That means you have to do this in a timely manner if you don’t want to break the plug. You are not the only one to do this; you should not be focusing on trying to get the plug out.
You should have penetrating oil on as well. If the plug does end up fully loosening, that is great, but if it does not, you should apply some oil to it before leaving for a while. You need to do this again but you need to have a gentle back-and-forth rocking motion.
Step 6: Check the Threads
After removing the spark plug, check the threads from the cylinder head. Use a wire brush to remove any rust or carbon threads. Make sure the threads are in good condition so the new plug does not get stuck.
Step 7: Place the New Spark Plug
Before putting in the new spark plug, put a small amount of anti-seize compound to the threads (if the manufacturer recommends it). This is to prevent the plug from sticking and allows it to be removed easily during the next spark plug changing.
Best Penetrating Oils for Stuck Spark Plugs
Every time you insert a spark plug, you should use a penetrating oil lubricant. This will ensure that you never get a spark plug stuck, as penetrating oil facilitates loosening when you have to remove it.
Do you want to know what the best penetrating oils are in the market? In this article we will answer that question.
1. Kano AeroKroil Penetrating Oil
Rating: 9.5/10
Time of use: 30 Years
Kano AeroKroil has the best penetration of all of the oils in the market for spark plugs. This oil has penetrated the market of trusted companies due to working well at loosening rust, corrosion, and any other bonds you have to remove when working with metal. It even works when it is warm.
Gets into Rusted Parts: AeroKroil is the best at getting into even the tiniest crevices and dissolving rusted and corroded stuck pieces. With this oil, you won’t have any issues in loosening stuck spark plugs.
Stays Effective: This oil has a long effective time. Other oils supply no long term effectiveness as they evaporate quickly. This oil is long lasting and removes spark plugs.
Versatile Use: Ideal for general mechanical repairs other than spark plugs.
Rust Dissolution: Rust and corrosion surrounding spark plug threads make unreimbursable damage to the cylinder head.
Pros:
- Extremely effective: It outperforms other oils in the removal of stuck and rusted spark plugs.
- Great for high-temperature environments: It doesn’t degrade yet withstands the heat generated in spark plug wells.
- Long-standing reputation: It has been used, and trusted, for decades by professionals and mechanics.
Cons:
- High Price: It comes at a higher price than most other penetrating oils.
- Low Availability: It may take longer to ship than some other oils in this category.
Ideal for: Working in high-temperature situations with excessively rusted spark plugs. Condensed engine parts means severely failing other oils, and thus this penetrating oil would be the most effective.
2. Liquid Wrench Penetrating Oil
Rating: 09/10
Liquid Wrench has a reputation as one of the best and cost-effective products on the market, making it a go-to for automotive and home repair for loosening rusted and stuck components. This product definitely has the prestige of being one of the best and cost-effective for loosening stuck components.
Fast Penetration: If you need a product that works in minutes, Liquid Wrench eliminates the need to sit and wait. It gets into the tight, rusted spaces of spark plugs and cylinder heads in no time.
Versatility: Liquid Wrench is effective for not only stuck spark plugs, but also, bolts, nuts, and other metallic components that are seized from rust.
Leave Behind Lubrication: This product helps to prevent future rust when it leaves behind a thin layer to help in the rust removal.
Safety: This product is safe to use on the rubber seals and wiring.
Pros:
- Effective on light to moderate corrosion: works well for removing spark plugs that haven’t been stuck for too long.
- Affordable: This cost-effective product is excellent for those on a budget.
- Fast-acting – Operates fast, resulting in less downtime when trying to remove a stuck spark plug.
- Widely available – Most auto-part stores and online sellers have a supply of Liquid Wrench.
Cons:
- Less effective on severe rust – Liquid Wrench works better than most penetrating oils, but if plugs have been stuck for years on end and are heavily corroded, it probably won’t work on them.
- Strong odor – While using it, some customers complained about having strong odors, which can be unpleasant during application of the product.
Ideal for: DIY enthusiasts – Finding an effective and inexpensive product to remove stuck spark plugs is a common problem for starters. This product is the solution.
3. Free All Rust Eater Deep Penetrating Oil
Rating: 8.5/10
Free All Rust Eater Deep Penetrating Oil is another one of those professional-grade penetrating oils that gets the job done. It makes the process of removing the most corroded and rusty mounting bolts super easy. Although its designed specifically for removing stuck and heavily corroded spark plugs, the oil is useful for any rusted bolt.
Rust-Busting Power: The main selling point of the product is that its designed to eat away at rust. As is the case with any deeply stuck spark plugs, rust is sure to be the primary problem.
Precision Nozzle: The oil comes with an easy to use, thick, plastic, yellow, pointer nozzle designed to thinly spray and direct the oil onto the threads of the rusted spark plugs. No more wasted overpriced product!
Fast Acting: As the product name suggests, this rust penetrator does the job of rust and corrosion penetrator in a matter of minutes!
Smooth Threads: The oil does help to provide some lubrication when removing the threads of the spark plugs. It helps to make removal easier and more frictionless to prevent damage and enhance ease onto the cylinder head.
Pros:
- Fast Acting: The oil does not waste any time getting the job done and is ideal for time sensitive repairs.
- Older Cars: The oil is perfect for any rusted and corroded bolts and is primary designed for older cars and neglected engines.
- Precision: The oil does does not waste any product with its thick yellow plastic nozzle.
- Automotive and mechanical parts versatility: It can also be used on mechanical and automotive parts other than just spark plugs.
Cons:
- Scent: It is one of penetrating oils and does have a very strong smell which can be really off-putting.
- More expensive: It is a bit more expensive than some other cheaper options.
Ideal for: Users of older vehicles or those with spark plugs that have corrosion or rust that has been building for many years.
4. CRC Ultra Screwloose Penetrant
Rating: 8/10
Designed as a penetrating oil for various purposes and applications. CRC Ultra Screwloose Penetrant works on spark plugs as well and is very popular for its ability to loosen even the most frozen of fasteners and fasteners that have rusted and wedged bolts.
Versatile formula: Works not just on automotive and spark plugs, but a whole host of rusted and stuck parts in other industrial or even household applications.
Thick, lubricating properties: CRC Ultra Screwloose has a reputation of having a thicker than usual penetrating oil, giving it advantage in lubrication.
Safe on Plastics and Rubber: It is one of the few oils that is safe, even around the rubber and plastic pieces of the engine which is very practical for automotive applications.
Long-Lasting Protection: Keeps future rust and corrosion at bay with a protective layer after the rust and corrosion is dissolved.
Pros:
- Good for a variety of uses: Works beyond spark plug removal and stuck part removal.
- Effective on rust: CRC Ultra Screwloose is one of the rust removers effective at corrosion breakdown.
- Lubrication: Keeps the rust more removal easy.
Cons:
- Thicker formula may be harder to apply precisely: When it comes to deep, tight spaces, thicker formula oils lose their edge when compared to thinner ones.
- May leave a residue: The product is sticky and requires cleaning after use but it keeps the rust off.
Ideal for: General use around the garages and workshops but especially for rusted parts that need both oil and more nutrient proprietary penetrations.
5. WD-40 Specialist Penetrant with Smart Straw
Raitng: 7.5
When it comes to lubricants, there are not many more recognizable than WD-40, and their Specialist Penetrant with Smart Straw is no exception. This penetrating oil is intended to get into tight spaces and loosen rust and corrosion from parts like spark plugs. This is especially great for the nozzle that helps to target smaller areas while applying the oil and makes it easier to manage.
Precision Application: This oil comes with a Smart Straw nozzle for great control while applying it to minimize overspray and waste.
Fast Penetration: Loosens rust and corrosion fast for ideal repairs.
Surface Safety: This product is safe to use with and on most surfaces of an automobile, even painted and rubber parts, which is a big plus when working near fragile engine parts.
Water Displacement: This formula helps eliminate moisture, and it helps prevent rust from forming in the future.
Pros:
- Brand Recognition: WD-40 is a trusted name when it comes to lubricants, and is used by many professionals, as well as DIYers, on a daily basis.
- Low Cost: This penetrating oil offers an economical option when compared to many of the more costly penetrating oils on the market.
- Smart Straw nozzle for precision: The straw nozzle is an awesome feature for applying the product exactly where it is needed.
Cons:
- Not as effective on heavy rust: WD-40 helps with light to moderate corrosion, but if you have severely rusted plugs, it may not be strong enough.
- Leaves residue: It has been reported by some users to leave a film that will require some cleaning after you are done with the product.
Ideal for: Beginners or for people that already do multiple tasks with WD-40, as it is a light to moderate rust and corrosion product.
Frequently Asked Questions
Here are some FAQs about best penetrating oil for stuck spark plugs –
- Can I use WD-40 and/or regular oil instead of penetrating oil?
While regular oil and WD-40 will give you lubrication, those products will not break down rust or penetrate tight threads. All the penetrating oils, like the ones in this guide, are made to deal with tough and rusted stuck parts.
- How long should I let the penetrating oil sit to remove the spark plug?
For best results, let the oil sit for 15-30 minutes. If the plug is stuck in place, you should let the oil soak in for the entire night to loosen the plug effectively.
- Will my engine get damaged from using too much penetrating oil?
Using a little bit of penetrating oil around the threads of the spark plug is fine. Using too much can soak into the combustion chamber and cause fouling. Just be sure to wipe off excess oil whenever you can.
- Can spark plugs break because of the oil?
Penetrating oil will not cause spark plugs to break when it is applied properly. If a stuck plug is damaged, it is typically because of too much force having to be applied when removing it. Just make sure to use gentle and gradual force when doing this.
- How to ensure spark plugs don’t get stuck again in the future?
To minimize problems, make sure spark plugs get installed properly, properly torque to manufacturer’s specs, properly clean the spark plugs to avoid moisture and debris build up, and use anti-seize compound if specified by the manufacturer.
Conclusion
Getting a spark plug out that is rusted and stuck can be a very frustrating job as well as expensive if you get it done by a professional. The right penetrating oil can make a job that is very difficult, easy. Picking a penetrating oil that has excellent penetration ability, rust-dissolving power, as well as some temperature resistance and lubricating ability is the right way to go. This is why products like Kano AeroKroil and Liquid Wrench, and Free All Rust Eater have been on the market for long when it comes to removing stuck spark plugs.
Applying the oil is the easy part. It is the patience and the right technique that will allow you to overcome removing stuck spark plugs without damaging your engine. It is all about calming down and following the right steps to make sure that the process of removing a spark plug is done efficiently and as easy as possible with the right penetrating oil.
