10 Best Penetrating Oils for Exhaust Manifold Bolts [REVIEWS]

When repairing exhaust manifolds, you’ll come across rusted fasteners and stubborn bolts. That’s because as the car ages, exhaust manifold bolts tend to become rusted or corroded. As a result, they’re left stuck in place, making them quite difficult to deal with. 

Thankfully, penetrating oils are a simple solution for handling those heavily oxidized bolts and studs. So if you’re wondering what is the best penetrating oil for exhaust manifold bolts removal, today is the day!

We’ve reviewed some of the top-quality, low viscosity lubricants that penetrate in the narrowest spaces between the threads of your exhaust bolts.

And here’s a Quick round-up with our top 3 choices:

Image Name Rating Price
WD40 Multi-Use Penetrant for Exhaust Manifold Bolts

5 out of 5

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Gasolina Free All Deep Penetrating Oil for Exhaust Bolts

5 out of 5

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Kano Aerokroil Penetrating Oil for Seized Bolts

4.5 out of 5

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To read about our product selection procedure, visit the “About” page.

10 Best Penetrating Oils for Exhaust Manifold Bolts [REVIEWS]

These oils will displace or dissolve rust in the joint of the exhaust manifold bolts. And leave a thin oil coating on the surface. Hence, allowing you to loosen the frozen bolts with ease. Better still, these lubricants prevent the bolts from rusting in the future.

That’s said, here’s our top pick (best choice product) to start off criticizing!

1. WD40 Multi-Use Penetrant for Exhaust Manifold Bolts

Established in 1953, WD-40 is one of the most popular multi-purpose lubricants available. Interestingly, the ‘WD’ in this brand’s name stands for water displacement. While the ‘40’ represents the number of attempts it took Norman Larsen to invent this formula.

Apart from that, this penetrant for rusted exhaust manifold bolts has many applications. In this case, it acts as a great penetrating oil for old studs on exhaust manifold systems. Thanks to its ability to remove rust and corrosion.

Besides, its water displacement formula protects the surfaces from rust.

Moreover, you can use this formula to lubricate metal surfaces. Not to forget that it dissolves tough grime, grease, and residue on various surfaces as well. For that, it’s a great product for cleaning greasy automotive parts, tools, shop floors, and commercial appliances.

Moving on, this water-based aerosol is safe to use on various surfaces. You can use it on metal, wood, rubber, and most plastics. However, it’s not suitable for use on clear polystyrene plastic & polycarbonate.

As for the packaging, this penetrating oil comes in the WD40’s iconic blue-&-yellow 12 oz spray cans. More notably, the can is fitted with a smart straw and features a 2-way spray system. This allows you to reach areas other oils cannot reach since you can either use it upright or upside down.

The only thing you need to note about this product is that it’s invasive in nature. For that, it can soften car polishes, rubberized synthetics, and unsealed bearings. Other than that, it’s suitable for loosening stuck and rusted bolts and nuts.

2. Gasolina Free Best Penetrating Oil for Exhaust Bolts

Gasolina Free is a fast-acting formulation that contains a powerful rust-dissolving agent. It will quickly penetrate into rusted exhaust manifold bolts for convenient removal. Even better, this oil has a lubricating film.

This will prevent it from evaporation, ensuring the task goes on smoothly. It’s worth mentioning that this penetrating oil is designed with versatility in mind. So, apart from using it to remove frozen nuts and rusted bolts, it is ideal for other applications as well.

For instance, it removes rust and frees metal objects like gates, hinges, and fences. Moreover, it is efficient at freeing up rusted machine screws and automotive clamps.

Still, this formula is suitable for loosening grease, graphite deposits, white & red lead, and tar. Yet it’s free from harsh chemicals like silicone. This makes it more eco-friendly than some oil penetrants out there and safe for indoor use.

That aside, applying this penetrating oil to rusted bolts is quite simple. For starters, it’s available in an 11 oz aerosol can fitted with a precision straw. Better still, you can either spray the oil through the straw nozzle or in the wide-aim nozzle.

Either way, this makes it easy to apply the oil with high accuracy.

Overall, Gasolina’s fast-acting formula will help you free jammed exhaust manifold bolts right away. Best of all, it will protect them against future corrosion and you can use it for other applications.

3. Kano Aerokroil Penetrating Oil for Seized Bolts

At first glance, Kano Aerokroil may not have the most innovative packaging. Well, don’t let that delude you! It’s still one of the best penetrating oils for seized bolts you’ll ever come across. Besides, it’s the most trusted penetrant by professionals when it comes to loosening stubborn fasteners.

First, this product penetrates into extremely small cracks and spaces. According to scientific research, it can penetrate into gaps that are as narrow as 1/1000000 of an inch. Therefore, it will easily access even the furthest stuck mechanical parts.

As a result, those components will be easy to loosen and remove.

Besides, the 10 oz. spray can this formula comes with direct application. Its convenient applicator helps to apply a small amount of the formula with precision. Best of all, this formula doesn’t expire, meaning you can use it for a very long time.

On the same note, it lubricates the metal parts, gives them rust protection.

Apart from loosening frozen threads, this penetrating oil has many other applications. For instance, you can use it to dissolve dried grease, gum, and oil from metal parts. And as we said earlier, it provides lubrication, displaces water, and prevents rust.

On the downside, this penetrant for exhaust manifold bolts is a bit costly. So, if you’re operating on a budget, it may not be the best option for you. Nonetheless, considering it will last you a lifetime, it may be a worthy investment.

4. Liquid Wrench L116 Rusted Stud Penetrant

Liquid Wrench is a famous family-owned brand widely known for producing high-quality penetrating oils for rusted bolts. With L116 being one of the most popular products when it comes to rust removal. That shouldn’t surprise you though, seeing that the company has been around since 1941.

Moreover, they manufacture various automotive and industrial products such as greases and lubricants. However, in this article, we’ll only go through their best liquid wrench penetrating oil review.

Unlike the penetrating oils we’ve looked at so far, this formula doesn’t come in an aerosol can. Instead, it comes in the form of a liquid formula packed in a 16 oz bottle. Nonetheless, it’s very effective in dissolving rust and cutting through grease.

Therefore, it’s suitable for freeing up any stuck nuts, locks, bolts, and latches. Moreover, it’s a great lubricant and it’s safe for use on painted and plastic surfaces. However, avoid using it on stain-prone materials like cloth and wood.

Another benefit of using this formula is that it’s free from VOC and it has a yellow color. Instead, it’s made up of TMP Tri-foliate Polyol Ester, hydrocarbon fluid, and carbon dioxide. Besides, it produces a minimal smell, making it ideal for indoor application.

Lastly, it has low surface tension, allowing it to penetrate into rusted parts with ease. This will help you to free rusted mechanical parts. Also, you can use it as a general cleaner, lubricant, or rust-prevention solution.

5. CRC Screwloose Super Penetrant Oil

When CRC was established in 1958, it only had one multi-purpose lubricant known as Corrosion Inhibitor. However, the company manufactures more than 1300 formulas for various industries today. One of those products is this Screwloose Super Penetrant Oil!

In essence, this penetrating oil attacks corrosion and rust in metal components. More importantly, its strong, fast-acting concentrated solvent penetrates tightly fitted crevices instantly. Hence making it easy to loosen and free corroded and rusted fasteners.

Moreover, this solvent doesn’t evaporate because of its slow evaporation rate. Instead, it leaves a durable non-dry-filming on the surface to prevent corrosion.

As for the ingredients, this penetrating oil features a petroleum distillate base. On the same note, it’s NSF H2-certified and VOC-compliant, so it’s safe for use in every state in the USA. Also, you can use it on water and food sources intended for human consumption.

As an example, it’s ideal for use in food processing facilities including meat and poultry plants.

Still, on use, this product can be applied on various surfaces. For instance, you can use it on plastic, locks, bolts & nuts, sliding mechanisms, bushings, hinges, and so on. Also, it’s suitable for use in the fixture, furniture or mechanical equipment with movable parts.

The only challenge this product may have is that it lacks a nozzle precision applicator. Apart from that, it performs effectively, and it’s free from dyes and ozone-depleting chemicals.

6. Liquid Wrench L112/6 Penetrating Oil Spray

To handle tougher rusty bolts, you’ll need a penetrating oil that is equally tough. Otherwise, loosening the bolts will seem like an almost impossible task. That’s where this L112/6 penetrant spray from Liquid Wrench comes in.

With its consistent formula, this oil is suitable for professionals and starters alike. Even better, it’s quite affordable, yet it can effectively loosen any stuck bolts.

Other notable properties displayed by this oil are low viscosity and high levels of lubricity and solvency. On top of that, it features low surface tension. It flows into very tiny spaces and threads while cutting through tough grease and rust.

The formula works quickly, so you’ll see the expected outcome within minutes. Besides, this penetrant oil is free from Volatile Organic Compounds. Therefore, you can safely use it on metals, painted surfaces, PVC, and plastic.

Unlike the Liquid Wrench penetrating oil we looked at earlier, this product comes in an 11 oz. spray can. Therefore, it’s much easier to apply since it allows you to loosen stuck bolts and locks in an accurate manner.

In addition, the aerosol can feature a new and advanced spray pattern. This generates enough power to get the oil into the crannies and nooks of frozen mechanisms. Besides, the formula produces a low smell, so you can simply apply it indoors.

Generally speaking, L112/6 has all the factors of a quality penetrating oil. To be precise, it has low viscosity, low surface tension, and high lubricity & solvency. These factors make it the best oil penetrant for studs on exhaust manifolds.

But you can use it to cut through the toughest grease as well.

7. B’laster 16-PB Penetrating Catalyst for Car Engine

Since its establishment in 1957, B’laster has developed into the top-selling penetrants. It has many great properties, but that is mainly attributed to effectiveness and affordability.

To start, this formula makes it easy to remove any frozen, rusted, or stuck component. As such, you can use it on automotive parts like bolts, nuts, bakes, and suspension and exhaust systems. Besides, it helps the components from future corrosion.

Hence making it suitable for plumbing and marine applications as well.

Another notable property of this formula is that it has a low viscosity. As you may have guessed, this makes it easy to pour at a certain temperature. Moreover, this minimizes surface resistance, allowing it to creep into components without any issues.

Like other quality penetrants, this formula has a non-evaporating lubricant. As a result, the oil stays on the surface longer, providing lubrication to the moving parts. Also, the lubricating film protects the metal component from future corrosion and rusting.

As a drawback, this formula tends to produce a lot of fumes on applications. This can cause various eye problems including eye irritation. Therefore, it’s good to wear goggles and work in an open space when applying this penetrating oil.

Also, make sure you wear a respirator to prevent chemical inhalation. While still on the limitations, avoid using this penetrating oil on plastic materials.

Putting those drawbacks aside, B’laster penetrant is far more superior to most products out there. All thanks to its affordability, efficiency, and consistency when handling seized bolts.

8. Trick Shot Penetrating Lubricant for Bolts

If you want an eco-friendly, but high-performing penetrant, this product from Trick Shot may be the ideal option for you. That is because it’s made up of 100% biodegradable, non-toxic ingredients. Moreover, it’s non-flammable as well as safe for the environment and waterways.

In addition to being environment-friendly, this formula is very versatile. For instance, it’s suitable for use in industrial, automotive, and marine applications. Its non-toxic nature makes it ideal for household, food processing, and agricultural applications.

Some of its uses include; fighting corrosion, cleaning, and lubricating moving parts. More notably, it’s one of the best penetrating oils for unlocking seized parts.

The other benefit of Tick Shot penetrants is that it’s very simple to apply. For starters, the formula comes packed in an 11 oz aerosol can with a straight shooter nozzle. This unique nozzle minimizes overspray by allowing you to hit the target with precision.

Besides, this makes it easy to apply the penetrant in vertical threads of fasteners and bolts. While helping it to penetrate into close tolerance parts to loosen stuck or rusty components. Moreover, applying a light film protects various metals against corrosion and rust.

Note, this product does more than loosen stuck parts or fight corrosion. As an example, you can use it to lubricate rotating and moving parts like rollers, pulleys, and hinges. Thus helping to reduce friction and eliminate squeaks.

Finally, you can use a cleaning or degreasing agent to remove gum, tar, and scuff marks.

9. Blaster PB Penetrating Lubricant for Studs

Unlike other penetrating oils we’ve reviewed, this PB Blaster penetrating oil comes in a pack of 12. That will help you save money and use it for longer. So, if you encounter stuck parts regularly, you should consider buying this penetrant.

Besides, that’s one of the many reasons it’s a popular option among professionals and DIYers alike. Now, moving on to its properties, this formula doesn’t evaporate.

Its flashpoint, or the temperature at which it explodes, is around 152 deg Fahrenheit. For that, it’s safe to use under various circumstances and provides rust protection.

Another notable feature of this penetrant is that it’s made up of a powerful ingredient mix. This helps it to access those tight activities conveniently and in minimal time. On the same, the nozzle on the 11 oz cans has small openings.

Therefore, you just need to apply a small amount to the solution for it to work. This ensures that IT seeps through even the smallest cracks, spaces, and crevices.

On application, the formula removes rust and loosens the surface tension. As a result, loosening rusted exhaust manifold bolts and other parts becomes much simpler. Best of all, this formula leaves a lubricating film behind, preventing further rusting.

As we said earlier, the problem with Blaster lubricants is that they tend to leave some odor behind. Not to forget that this formula can also cause skin and eye irritation. So, make sure you wear protective clothing and work in an open/ well-ventilated space.

10. APEL Industrial Penetrating Oil for Bolts Removal

Similar to the Blaster PB penetrant above, this product from MITREAPEL comes in a pack of 12 spray cans. However, these cans are smaller in size, since each unit has a capacity of 6.78 oz. Nonetheless, it contains a unique formula that allows you to loosen exhaust manifold bolts, screws, and more.

The most unique feature about this penetrating oil is that it’s simple to apply. Besides, you just need to spray it directly onto the rusted surface and leave it for a minute. After that, wipe the surface clean and the stuck part is ready to be loosened. That’s it!

But, what makes this formula so effective?

First, this penetrant has a fast-acting formula. Thus helping it cut through rust and corrosion in the shortest time possible. In return, this allows you to work on stuck bolts, screws, and nuts in no time. Also, this special formula contains powerful, anti-corrosion ingredients.

These agents prevent future corrosion and rust while lubricating the surfaces. Best of all, these penetrate into any crack and crevice with ease. As a result, loosening the gunk and rust holding your exhaust manifold bolts tight becomes very simple.

Lastly, this formula does more than cut through rust to help you loosen stuck parts. Instead, it’s suitable for many other applications such as lubricating moving parts. Besides, it makes it easy to disassemble tools and machinery.

Things to Consider when Choosing a Penetrating Oil for Exhaust Manifold Bolts

When choosing a penetrating oil for exhaust manifold bolts, there are certain factors you need to consider. Otherwise, it will be hard to know whether you selected the right product or not. Some of those factors may include;

Viscosity & Lubricity

Viscosity refers to the measure of the fluid’s internal friction. In essence, the penetrating oils should have low viscosity. This allows them to seep through tight spaces with ease.

With that in mind, avoid choosing penetrants with high viscosity levels. Using such fluids will increase the chances of damaging stuck components further.

On the other hand, lubricity is the fluid’s ability to reduce friction and wear in moving components. If you’re planning to use the penetrant in mechanical parts, choose a product with a durable lubrication action.

In other words, it should leave behind a thin liquid film to ensure smooth motions. Also, that film will prevent future corrosion by protecting it from rust and moisture.


Most penetrating oils come packed in a spray can. However, this doesn’t necessarily mean that all products are easy to apply. For that, it’s good to check if the can has features that promote a convenient and precise application.

For instance, check if the spray is fitted with a straw to ensure accurate application. Moreover, this will minimize oil wastage and allow fast and effective oil application.

Type of Penetrating Oil

Penetrating oils come in different types since they’re designed for different purposes. That’s why it’s important to choose the right oil type based on the intended application. Similarly, the formulation of these solvents tends to vary as well.

Nonetheless, some ingredients are common in most penetrants. But some products may omit critical substances or include various additives. Either way, make sure you check the type of formula you want before you choose a penetrating oil.


All penetrating oils on our lists are suitable for use on exhaust manifold bolts. However, some products are ideal for use on many other materials. You can apply such penetrants on metal, painted surfaces, rubber, and most plastics.

Before you choose a certain oil, ensure it’s compatible with the surface you intend to apply it on. Still, on versatility, look for a penetrating oil that does more than loosen rusty bolts. That way, you can use it for various applications like cleaning, rust removal, and cleaning.


When it comes to finding a penetrating oil for rusty bolts, there are so many options to choose from. However, finding the perfect option for your applications may not be an easy task.

Fortunately, by going through our reviews, there is a good chance of finding a product that will suit your job. Besides, these penetrants are high-performing options in handling rusty mechanical components!


1. Does penetrating oil really work?

Yes! Due to their low viscosity, penetrating oil quickly seeps through threads and rust in tight spaces. More importantly, they break the bonds of stuck and rusted parts, making it easy to loosen them. In addition, they leave a thin lubricant film behind, preventing the formation of rust in the future.

2. What can I use instead of penetrating oil?

ATF (Automatic Transmission Fluid) or vegetable oil with 5% acetone can be used in place of penetrating oil. Besides, you can boost the performance of these fluids further by increasing the content of acetone.

3. Does WD-40 work on rusted bolts?

WD-40 penetrant spray is one of the best products for loosening stuck bolts because of rust. This formula penetrates the fitting with ease, allowing you to loosen the bolt.

4. Will heating a bolt loosen it?

Applying heat to one side of a seized nut can help to loosen it. The heat causes the nut to expand, thus breaking the rust bond. To make the process much simpler, apply some penetrating oil before you heat the seized component.

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