Best Sealant for Differential Cover

11 Best Sealant for Differential Cover – Reviews & Buying Guide

Sealing the differential cover helps prevent oil leaks and keep out impurities that could cause oil contamination. But that is not possible without a suitable sealant.

The best sealant for differential cover creates a tight bond that keeps a vehicle’s differential gears safe. It creates a tight bond between the two mating surfaces, which couldn’t be possible without it.

It isn’t enough to use just a gasket. Pre-cut differential gaskets may fail to cover irregular surfaces adequately. It would help if you had a sealant to fill in any holes, crevices, and gaps.

This article discusses sealant for differential cover, providing detailed reviews of 11 products in this category. At the end of the article, there is a detailed buying guide for sealants. Keep reading to learn more.

What Is Differential Cover Sealant?

A differential cover sealant is a product that stops small leaks that manifest in an engine differential. It can be used with a solid gasket to provide strength, increase adhesion, and improve water/chemical resistance. A differential cover sealant closes any holes through which oil might leak, improving the engine power.

Differential Cover sealant

The differential cover sealant may come in different forms, including Room Temperature Vulcanizing (RTV) that cure at room temperature, the anaerobic sealant that doesn’t set hard, and non-setting compounds. The sealant may also come as a liquid that creates a seal without a solid gasket.

Our 11 Best Sealant for Differential Cover Review

Here are the best and high-quality Sealants for Differential Cover that are worth considering.

1. J-B Weld 31914 Red High-Temperature RTV Silicone Gasket Maker and Sealant

The J-B Weld 31914 is a high-temperature silicone gasket material that works in mechanical assemblies with 550°F to 650°F temperatures. It is suitable for making gaskets for differential covers when you cannot buy a new one.

It is one of the best sealants for differential cover for professionals like builders, repair workers, and mechanics.

The product creates a strong bond on varied surfaces regardless of how challenging the environment is. You can always trust this product to give you the best possible results.

While the sealant is excellent for professionals, virtually anyone can use it. It is a DIY differential sealant.

Apply it to the crack or differential surface and wait for a few minutes for it to cure and dry in the air. It creates a rugged, waterproof seal that doesn’t crack or shrink under any conditions.

Of course, J-B Weld 31914 is an incredible differential sealant. However, that isn’t the only function you can use.

The differential cover sealant works well on oven doors, drive housings, differential covers, timing covers, water pumps, exhaust manifolds, oil pans, metal, and automotive parts. Its dependability makes it stand out from similar products.

Highlighted Features

  • An easy-to-use DIY sealant
  • Fast-drying when exposed to the air
  • Forms a strong bond on various surfaces
  • Versatile and multi-purpose
  • Withstands temperatures between 550°F to 650°F

2. Permatex 27036 Optimum Grey Gasket Maker

Permatex 27036 is one of the best sealants for differential cover due to its non-corrosive, low-odor, and sensor-safe capabilities. It can, therefore, creates an effective gasket on your engine differential without eroding it. Besides, it won’t make you uncomfortable with a strong odor.

The 3.35-ounce sealant is oil-resistant and vibration-resistant, working perfectly well in an engine differential. It also works well in environments with shop fluids and cooling fluids.

Manufacturers of this sealant intended to use it in engines where temperatures can be extremely high. The sealant can resist extremely low or high temperatures of -65°F to 700°F. Therefore, its temperature resistance is 40% higher than usual.

Permatex calls this product the most advanced high-temperature RTV silicone sealant on the market today. They might have a point on that aspect, especially when using it in heavy-duty diesel engines.

The package includes two nozzles so that you can easily replace a clogged one. Besides, the two-nozzle operation makes it easier to put each tube to multiple uses.

Apart from differential covers, the sealant is also great on timing gear covers, intake manifold end seals, oil pumps, oil pans, and valve covers.

Highlighted Features

  • Resists low temperatures (-65°F to 700°F)
  • Oil-resistant
  • Vibration-resistant
  • It comes with two nozzles
  • Multi-functional sealant

3. Genuine Ford Fluid TA-31 RTV Silicone Sealant

Ford is one of the biggest vehicle manufacturers globally, so you would expect them to make an excellent sealant for differential cover. So, they developed this specially-designed alkoxy cure sealant for high-temperature applications.

The Ford Fluid TA-31 RTV Silicone Sealant can work in any engine part, including the differential. It is non-corrosive and can protect your engine from deterioration due to interaction with the elements.

Its high-viscosity material starts curing within a few minutes to the air. Therefore, you don’t need to carry out any special procedures to cure sealant. However, you must wipe the surface clean before using the sealant.

The sealant is formulated for automotive use, which is the reason you shouldn’t shy away from using it on your engine differential cover. Its manufacturers recommend the sealant in 6.0L, 6.4L, and 7.3 power stroke diesel engines.

One reviewer who had previously worked at Ford Corporation says the sealant is so effective that you can use it to assemble a whole vehicle. It doesn’t break down when exposed to rain, snow, and the sun, providing the perfect differential cover.

Highlighted Features

  • Great for high-temperature applications
  • Great for large diesel engines
  • Instant curing
  • Non-corrosive properties
  • Specially designed for automotive use

4. Loctite Sealant, High-Flex Gasket Maker

Loctite is one of the best sealant brands on the market. It makes the best sealants for differential covers, capable of working in environments with extremely high temperatures. The sealant has a silicone formula that dries quickly to create water-resistant, oil-resistant, and vibration-resistant covers.

It provides a five-times stretch and excellent strength, providing an airtight seal in the differential and other parts of the engine. Apart from metals, it can seal all types of materials. It can provide fast curing after application, providing a quick fix to your engine differential.

The Loctite Sealant, High-Flex Gasket Maker, is available in a 50ml tube measuring 7″ x 1.7″ x 2.3″, making it highly portable. It is a product of the United States, which means that it’s produced according to the highest possible standards.

Users who applied it on uneven, imperfect surfaces have said it’s incomparable to any other product on the market. Apart from making differential covers, it can help you repair hydraulic pumps and other engine parts. It is, therefore, a reliable sealant that holds tightly and doesn’t pull apart quickly.

Highlighted Features

  • Can withstand high temperatures
  • Water-resistant, oil-resistant, and vibration-resistant
  • A fast-drying sealant
  • Works well on uneven surfaces
  • A multi-purpose sealant for differential cover

5. Permatex 81182 Gear Oil RTV Gasket Maker

Here is another product from Permatex featured in this review. The Permatex 81182 has a formulation that withstands the harsh environment created by gear oil, especially in differentials. Therefore, it is an effective sealant for differential cover, securing one of the engine’s most sensitive parts.

It features specialty silicone that cannot break down when exposed to gear oil, water, or engine vibrations. Besides, it can resist the extremely high temperatures that are sometimes created by the engine.

If you’re having trouble sealing leaks with cut gaskets, look no further than this particular sealant. Its makers say it actively seeks and seals all leak paths that cut gaskets cannot. That’s primarily on uneven or irregular surfaces where a gasket might not cover adequately.

Before release to the market, the sealant was tested to OEM (original equipment manufacturer) specifications, ensuring it delivers complete sealing power wherever you use it.

Apply after cleaning surfaces and drying with a designated residue solvent. The product is certified to be non-toxic, sensor-safe, and non-flammable. Therefore, it can work well in an engine without melting down in the heat.

Highlighted Features

  • Gear oil-resistant
  • Made from specialty silicone
  • Tested and proven to provide complete sealing power
  • Non-toxic
  • Non-flammable
  • Sensor-safe
  • Seals difficult leaks

6. J-B Weld 31919 RTV Silicone Sealant

The J-B Weld 31919 is an effective sealant for differential cover, providing exceptional performance in conditions with high temperatures and engine oil. It is a multi-purpose room temperature vulcanized (RTV) silicone that seals and bonds uneven surfaces better than cut gaskets.

It is the number one product preferred by professional repair personnel, mechanics, and builders. The sealant bonds firmly with various surfaces, including tough and uneven ones. If not for any other reason, choose this product because of the faith the pros have in it.

The J-B Weld 31919 forms a rugged, waterproof gasket on all surface types as soon as it cures. Therefore, you shouldn’t expect it to crack or shrink under pressure. The resultant differential resists weathering, making the sealant ideal for for use in vehicles and domestic settings.

With this versatile product, you can use it for sealing, bonding, interior trim, weatherstripping, windshields, windows, lens housings, door frames, and so on. Therefore, you don’t have to restrict it to only one function.

Finally, you don’t need to be a qualified mechanic to use this sealant on your differential. It is a DIY product capable of repairing and restoring engine parts as soon as you apply it. You’ll be surprised how easy it can create a strong bond.

Highlighted Features

  • It is a room temperature vulcanized (RTV) sealant
  • Works on smooth and rough surfaces
  • Easy to use even for DIYers
  • Multi-purpose and multi-functional
  • Crack and weathering resistant

7. ATP AT-205 Re-Seal Stops Leaks, 8-Ounce Bottle

If your differential cover has problems or wants to create a completely new one, the ATP AT-205 sealant is the go-to product. It is a fast-acting re-sealer that provides professional strength and stops engine leaks quickly.

The sealant is capable of rejuvenating all the rubber seals and gaskets in your engine, power steering, transmission, hydraulic system, and differential. Therefore, you can use it together with existing gaskets in all engine parts.

It comes in an eight-ounce bottle, which is small and high-portable. The quantity is enough to treat a surface requiring 6 quarts of sealant. Applying it is easy and requires you to pour it into the differential together with the oil. It circulates throughout the engine, treating and conditioning rubber gaskets and seals.

The best sealant for differential cover is compatible with hydraulic oil, power steering fluids, gear oil, ATF, synthetic oil, conventional oil. Regardless of which part of the engine you use, the sealant works perfectly fine.

Given that it has zero elements of petroleum distillates, the product doesn’t over-swell. Besides, it cannot contribute to the breakdown of seals in any part of your car engine.

Highlighted Features

  • Works in multiple automotive systems
  • Targets old rubber gaskets and seals, rejuvenating them
  • Available in an 8-ounce bottle
  • Easy application by mixing with oil
  • Seals most automotive leaks in five hours

8. Genuine Chrysler Accessories (4883971AB) RTV Silicone Rubber Adhesive Engine Sealant

The 4883971AB is a genuine Chrysler accessory designed to improve automotive rubber seals and gaskets adhesion. One area that needs this product to block out leaks is the differential. You can trust it to work effectively, given that its manufacturer is one of the biggest automotive manufacturers in the world.

It effectively seals various parts of the vehicle engine, including power steering, transmission, hydraulic system, and differential. Unlike cut gaskets, which only work on perfectly smooth surfaces, this particular product is effective on uneven, irregular, rough surfaces.

The specially-formulated automotive sealant effectively seals parts of the engine exposed to oil. Coming into contact with oil doesn’t reduce the adhesive properties of this black silicone RTV. Instead, the product retains its sealing properties and effectively stops oil leaks in all their manifestations.

Those who have previously used this product say they didn’t see any oil leaks afterward. That’s hardly surprising, considering this is a genuine original engine manufacturer (OEM) Chrysler fluid. The 0.07-pound tube measures 8 x 4 x 2 inches, making it highly portable.

Highlighted Features

  • Effectively improves adhesion in existing rubber gaskets
  • Works in different parts of the automotive engine
  • Its formulation blends well with engine oil
  • Genuine OEM Chrysler fluid
  • For use in automotive engines and differentials

9. Pro Seal N80729 Hi-Temp RTV Silicone Instant Gasket

With the Pro-Seal N80729, you can stop oil leaks in the differential and other parts of the vehicle. It’s available in an 8-ounce power can, weighing 3.01 pounds. If you want an effective product to replace pre-cut gaskets, look no further than this.

According to the manufacturer, this is a high-temperature product ideal for automotive engines. It can resist low temperatures of -70°F and highs of 650°F without cracking or breaking down.

You can use it in any vehicle engine differential, regardless of the car make or model. Its manufacturer says the sealant can resist high pressures of up to 5,000-pounds-per-square-inch, leaving it intact for a long time as a differential cover.

It takes less than ten minutes to apply to the area that needs sealing and can take up to 24 hours to fully cure. Coming in touch with oil, transmission fluids, and grease doesn’t diminish the sealant’s adhesive capabilities. It also has antifreeze properties, makin   g it versatile and unbreakable.

After drying, the sealant creates a flexible gasket that doesn’t crack or shrink under pressure. The USA-manufactured sealant is reliable, providing incredible results all the time.

Highlighted features

  • Made in the USA
  • Available in an 8-ounce can
  • Great replacement for pre-cut gaskets
  • Works in any car model
  • Pressure and heat-resistant
  • Easy application
  • Flexible when cured

10. Mission Automotive Dielectric Grease/Silicone Paste

The automotive dielectric fluid seems to be on a mission to close all leaks in your vehicle’s differential, what with its greasy thickness. It is a long-lasting waterproof synthetic silicone lubricant designed to inhibit corrosion, prevent oxidation, and seal out dirt, salt, and other contaminants. The formulation can resist extreme temperatures between -55°F and 570°F, maintaining consistency, stability, and avoiding melting down.

It has a unique silicone formulation that comes in the form of a paste for use in various automotive functions. The sealant works perfectly well whether you use it on plastic, rubber, or metal. It prevents oil leaks in engines and voltage leaks in electrical connections.

The multi-purpose sealant is excellent for use in differentials, weatherstripping, hoses, O-rings, rubber caliper pins, and spark plugs. You can also use them to fix broken car windows effectively.

It comes in a 0.24-liter bottle accompanied by an applicator brush for easy and effective installation. The sealant can be clear, transparent, translucent, or slightly milky. Don’t worry about the color. It works perfectly fine regardless of how it looks.

Highlighted Features

  • Works as grease and sealant
  • Multi-purpose application
  • The package includes an applicator brush
  • Prevents oxidation and corrosion
  • Manufactured with the highest standards

11. BlueDevil Oil Stop Leak

If you’re looking for an effective way to repair oil leaks in your differential permanently, this sealant from BlueDevil should be your first port of call. It locates and seals leaks that could be letting oil and other fluids seep through.

Half of the 8-ounce bottle is enough to use in a typical differential. Therefore, the entire bottle of BlueDevil can treat four to six quarts of oil.

The good thing about this BlueDevil product is that it works in all kinds of vehicles and engines. It is more affordable than having your car checked and fixed at the local repair shop.

BlueDevil Oil Stop Leak is made in the USA, a testament to its quality and ability to deliver its promises. It is a multi-purpose sealant great for differentials, weatherstripping, hoses, O-rings, rubber caliper pins, and spark plugs.

Highlighted Features

  • Made in the USA
  • It comes in an 8-inch bottle
  • For pouring directly to the oil
  • A multi-purpose sealant
  • Permanently seals

Things to Consider Before Buying Differential Sealant

Differential sealant

Before you head out to purchase sealant for differential cover, there are several things you must consider. Paying attention to the following ensures that you have a suitable sealant.

1. Heat Resistance

Differential temperatures can be extremely high, especially in trucks, which carry heavy loads. The oil and fluids in the differential can cause a spike in heat, melting ordinary sealant. When choosing sealant, make sure it can withstand extreme temperatures.

Some of the best products on the market can resist temperatures between -70°F and 650°F. Such a sealant has antifreeze properties and can withstand high temperatures. It not only stands against differential temperatures but can hold up in low temperatures.

2. Consistency

In most cases, differential cover sealant will come in a gel-like consistency. Some could also be in the form of lubricating grease. When choosing a sealant for differential covers, it’s essential to create the perfect balance on consistency. Too runny, and you could use too much of it. If the sealant is too heavy, you might find it hard to use. So, look for a product you can easily use.

3. Ability to Resist Pressure and Abrasion

When heat builds up in the differential, temperatures rise, and the oil or fluid expands, causing a spike in pressure. The easiest casualty is the rubber-like gasket or seal. You can ensure that the seal stays intact by picking one that resists extreme pressure and abrasion. While at it, don’t just take the manufacturer’s word but research, especially concerning what other people say.

4. Sealant Color

Silicone sealants come in many colors, transparent, translucent, red, grey, or black. Which one do you prefer? While the color doesn’t matter, it should match the part of the engine where you use it. For a differential cover, a gray sealant wound does an excellent job.

5. Ease of Application

Sealants may come in a bottle or tube. The sealant gets released through a small nozzle in a tube, making it easier to apply. Once you’re through, you can close the nozzle and keep the sealant for use on another day.

If you pick a bottled sealant, you may need a brush to apply it effectively. However, some sealants are applied simultaneously with an oil change. After adding the sealant to the oil, you give it time to locate leaks and stop them.

6. Resistance to Fluids

The purpose of a sealant is to seal the differential cover completely. It shouldn’t allow oil leaks from the inside and water leaks from the outside. So, make sure that you pick a sealant with oil-resistance and water-resistance properties.

7. Curing Time

If you’re pressed for time, pick a sealant that takes a short time to cure. While some take a few minutes to dry after exposure to the air, others may take up to 24 hours. Make sure you pay attention to how much time you have when choosing a sealant for a differential cover.

8. Ease of Removing

A sealant should make it easier for you to remove the differential cover to change the oil. It should be easier to access the differential when you need it. If the sealant is difficult to remove, use a sealant remover.

How to Seal a Differential Cover?

how to seal diff cover

When changing gear oil, it is necessary to seal the differential cover. Luckily, it is something you can do by taking the following steps:

Step 1: Carefully remove the differential cover, ensuring you have a bucket or catch basin underneath to prevent oil from spilling all over the place.

Step 2: Remove all the bolts, leaving the one above to let the fluid inside drain out properly.

Step 3: After Draining all the fluid, remove the last bolt followed by the cover.

Step 4: Scrape the gasket from the differential and the cover.

Step 5: Clean the two mating surfaces in preparation for covering the differential once again. Avoid using a metal brush, which can erode the metal. A nylon bristle brush is always the best to clean such surfaces.

Step 6: Cut the sealant nozzle and use it to create circles around the bolt holders. Using a thin line, connect all the circles. There is no need to apply too much sealant to even it out on the surface. Applying sealant to only one side of the differential cover is enough.

Step 7: Give the sealant time to cure and thicken. The waiting time depends on the type of sealant you have. Once it starts to thicken, replace the cover. Thread several bolts, wait for some time, and tighten the rest of the bolts.

Why It’s Necessary to Seal a Differential Cover?

The purpose of the gasket sealer for differential is to stop differential fluids from leaking. It keeps fluid inside, protecting it and the gears from water, rocks, dust, and other forms of contamination.

A differential cover is removable, making it possible to change the oil. It needs sealing to protect gears and prevent oil leaks.

Why It's Necessary to Seal a Differential Cover

Traditionally, pre-cut gaskets were used to seal differential covers. However, they are not practical due to irregularity or unevenness in the surfaces. Sealing is the better method due to the following reasons:

  • Filling in surface gaps to prevent leakages
  • Protecting gears inside the differential
  • Keeping fluid inside and preventing leakage
  • Protections against water, dust, and other contamination
  • Allowing easy access to the differential to service it

How to Stop Differentials from Leaking?

You can stop leaks in the differential using a high-quality sealant or a pre-cut gasket. Before sealing the cover, clean the mating surfaces. Scrape any left-over gasket until you only have the metal surface.

How do I stop my differential oil from leaking

Apply some of the sealants consistently on one of the surfaces. Allow the sealant to cure and put the cover in place. Tighten the bolts and remove excess sealant from the cover. Give it time to cure. Once it does, any leaks in the differential will stop.

Diff Gasket or Sealant – What are the Differences?

A gasket is a pre-cut rubber or silicone object placed between the differential to prevent leaks. It is solid and can be made from a variety of materials.

On the other hand, a sealant is a semi-liquid substance applied between a differential and its cover to prevent leaks. Since it’s semi-liquid, a sealant takes time to cure. A sealant essentially creates the gasket. Some sealants could be applied to the differential as part of the oil or fluid.

While a gasket and sealant serve the same purpose, one is pre-cut and solid, while the other is semi-liquid and used to make gaskets.

Frequently Asked Questions (FAQs)

Do you use RTV on the differential cover?

Yes. You should use RTV on the differential cover since that’s what most manufacturers use. All you need is to know the product you need and use it.

Does differential cover need sealant?

Yes. A differential cover needs a sealant to block potential and existing oil leaks. The sealant also keeps the water, dust, and other particles away from the gears.

What is the best sealant for differential cover?

The best sealant for differential cover is one that can withstand extreme heat and resist the effects of water, oil, and other fluids.

How do you use sealant on the differential cover?

You can use sealant on the differential cover in many ways. First, you can apply it to the surfaces. Second, you can add sealant to the oil.

Final Words

Now that you know how to buy the best sealant for differential cover, why don’t you go ahead and get one for yourself? Since this isn’t a product you buy every day, make sure you choose one that can seal your vehicle’s differential permanently. You don’t want to keep witnessing oil leaks. And you want to stop foreign particles from getting into the differential and messing up your gears.

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