What’s the Best Rear Main Seal Stop Leak? Here are the Best oil stop leak additives

A leaky rear main seal is a common problem with many cars.

The fluid seeping from the rear main seal can cause serious damage to your engine and an expensive repair bill.

If you’re noticing a fluid leak in the back of your car, then it might be time to invest in a rear main seal stop leak.

Below we provide you a review of 5 of the best rear main seal stop leak you can find on the market. We also provide answers to the most frequently asked question on this subject.

BlueDevil Rear Main Sealer additive

best rear main seal stop leak

The BlueDevil Rear Main Sealer is the best engine oil leak sealer for those looking for value.

It is a great brand and has great performance in stopping main seal leaks. This product is also quite cheap compared to others. It is simply a quick fix rear main seal leak for cheap.


Why do you need the best oil leak Best Rear Main Seal Stop Leak?

In recent years, more and more people began to pay attention to oil leak problems. These leaks are caused by the aging of the main seals after years of driving and as soon as they start leaking you need to find a rear main seal repair.

It makes our cars leaky, noisy, and smoky. By using the best rear main seal stop leak, you can have a much better driving experience and a cleaner garage.

Of course, it is best to take your car to an auto mechanic for a permanent fix. However, this solution may be expensive and unrealistic. With the best stop leak for oil on the rear main seal, you can have a cheap and easy-to-install quick fix.

One of the most serious oil leak problems is the main seal leak. It’s hard to find a suitable product for main seal leaks because there are hundreds of oil stop leak additives on the market.

Most of them are not specially designed for main seal leaks. They may be helpful, but they won’t work well.

So we tested different kinds of main seal stop leak additives to find out which one is the fastest and the most effective product.

We selected 5 out of dozens of the most famous products.

We rated them on speed, efficiency, safety, and price. These 5 products are considered to be the top rear main seal stop leaks.

What is the Best Rear Main Seal Leak?

Below is the review of the 5 best oil leak additives available in the marketplace.

  1. BlueDevil Rear Main Sealer
  2. ATP AT-205 Re-Seal Stops Leaks
  3. Bar’s Leaks 1040 Grey Rear Main Seal Repair Concentrate
  4. Hapco Products – Pro-Seal
  5. NO LEAK 20401 Engine Oil Stop Leak

1. BlueDevil Rear Main Sealer

best rear main seal stop leak

BlueDevil Products is a professional manufacturer of oil stop leak products. Most of BlueDevil products are fast, effective, and convenient.

What is blue devil rear main sealer, and is it bad for your engine?

The blue devil rear main sealer is an additive that can be mixed with engine oil to prevent engine wear. It is not bad for your engine if you use the blue devil rear main sealer additive.

Is Blue Devil a good product?

BlueDevil Rear Main Sealer is one of the best BlueDevil products and is designed for main seal leaks. You should have a try because it is the best stop leak for oil on the rear main seal.

You may be curious about the time it takes for BlueDevil to stop the leak. According to our tests, after we added Blue Devil in the oil, the main seal leak stopped after about 800 miles of driving.

Compared with its competitors, BlueDevil proved itself to be a better product as it actually stopped the leak while most of the others just slowed it or did nothing.

Because of its great performance, everyone in our lab agrees that this 8 oz product is good value for the money.

How to use BlueDevil rear main sealer?

BlueDevil Main Sealer is also easy to use. You don’t need any professional skills to use it because you just pour it in oil and drive. It works in gas or diesel engines, and it’s harmless.

The product will circulate and restore the strength of rubber parts especially the main seal.

For the best performance, you should drain the dirty oil and add a full bottle of BlueDevil right before oil changes. You should do it every 5000 miles to prevent future leaks.

Although this product restores all dried, cracked, and shrunken rubber seals, it may not work so well to stop other issues. To solve other oil leak problems, you should try some of Blue Devil’s other products.


2. ATP AT-205 Re-Seal Stops Leaks

ATP AT-205 Re-Seal Stops Leaks

ATP Automotive is one of the most well-known producers of rear main seal stop leak additives.

It provides dozens of products for different kinds of oil leaks. Most of the products have been used and accepted by customers all over the world.

They are effective and convenient. ATP AT-205 Re-Seal Stops Leaks is one of them, and it’s designed to be the best product to stop rear main seal leaks.

ATP AT-205 stops leaks very fast. It works on all rubber seals and gaskets in engines, transmissions, power steering, differentials, and hydraulic systems.

When solving main seal oil leaks, it performs flawlessly. According to our test, the leak was stopped completely after about 1000 miles.

ATP AT-205 is also a convenient product. When you are going to change the oil, simply pour a full bottle in, and drive.

It restores the strength of the rubber parts when circulating in your engine. It doesn’t contain any petroleum distillates that may over-swell or break down seals.

Finally, it is compatible with most kinds of oils on the market. So, you don’t have to worry about anything when you use ATP AT-205.


3. Bar’s Leaks 1040 Grey Rear Main Seal Repair Concentrate

best stop leak for oil on the rear main seal

Bar’s Leaks 1040 is the cheapest product for rear main seal oil leaks on the market. It doesn’t mean that Bar’s Leaks 1040 is not effective.

On the contrary, it works quite well on rear main seals. It can be a great rear main seal stop leak product if you properly use it.

Bar’s Leaks 1040 quickly restores seals that are worn or dried. Most rear main seal leaks are caused by not only the drying, hardening, and shrinking of the main seal but also normal wear in the crankshaft and seal.

All these problems can be solved by Bar’s Leaks 1040. You will see the leak has been stopped or at least slowed after several hours of driving.

To use Bar’s Leaks 1040, all you have to do is to add it to the oil before oil change.

You will see its effect after about 1000 miles. If you want to prevent future leaks, you should do it every 5000 miles. It works with all gasoline and diesel engines using conventional, high mileage, and synthetic oil.

The product sometimes doesn’t work because the rubber parts are too old and have broken into pieces.

We know we can’t save an old car simply with a 16.9 oz bottle of liquid. Nothing is wrong with Bar’s Leaks 1040. However,  when using cheaper products, people always expect more than what they can do.


4. Hapco Products – Pro-Seal leak product

best oil to stop rear main seal leak

If you have an oil leak problem with your main seal, you should try Hapco. Hapco Products Co. provides a top-end and best engine oil stop leak additive for those who want value.

Hapco works on all kinds of oil leaks, including the main seal oil leak. It’s been the best seller of the company since 1960, and it has been proved to be effective and convenient.

Hapco Pro-Seal works great as a concentrated leak sealant. If you have an old car and it leaks, the main seal leak can’t be the only problem.

There may be leaks or other problems with other parts such as main bearings, transmissions, power steering units, differentials, rack and pinion, and any hydraulic fluid system.

After using Hapco Pro-Seal, all the seal oil leaks will be stopped or slowed at least. According to our tests, it never causes any clogging, and it does no harm to any seals.

On the contrary, it restores flexibility, elasticity, and strength of rubber seals, and prevents future leaks.

Hapco Pro-Seal is also easy to use. The first step is to find the fluid reservoir where leaking is occurring. Then, you should add the product directly into the fluid reservoir. Don’t use it in your brake system.

If you want the best performance, you should use the full 8 oz of the product. Finally, drive your car as usual so that the product circulates and permanently brings the rubber seals back to their original condition.


5. No Leak 20401 Engine Oil Stop Leak additive

best rear main seal stop leak

No LEAK 20401 is a product for different kinds of oil leaks. It works especially well when dealing with a rear main seal oil leak.

If you have a main seal leak problem, this 16-ounce bottle of engine oil leak additive will permanently solve it. This product also does a great job when dealing with other oil leak problems.

Most seal oil leaks are caused by dried, shrunken, or harden seals. No LEAK 20401 restores their flexibility, elasticity and strength, stops the leaks and prevents future leak problems.

No LEAK 20401 is convenient, but simply pouring it into your oil may not be effective. It does not work with a leaky head gasket.

In that case, try a head gasket sealer. To stop the man seal oil leak, No LEAK 20401 should be added before the oil change.  Do as the instructions said and don’t overfill the crankcase. Your car will stop leaking after traveling several hundred miles.

No LEAK 20401 is cheap, so people may worry about its safety. According to our tests, No LEAK 20401 is compatible with all engine oils.

It basically brings rubber seals back to their original condition and does no harm to the engine. No LEAK 20401 is the best oil stop leak for the rear main seal if you use it properly.


What makes rear main seal leaks happen?

Rear main seal leaks happen when the rear main oil seal fails due to a broken or worn-out gasket.

When this happens, oil leaks out and can come in contact with the exhaust manifold or catalytic converter, causing a fire or serious engine damage.

What is a rear main seal of a car?

The rear main seal of a car refers to the rubber gasket that is positioned between the engine’s oil pan and the transmission. The oil pan is made of metal, but it has a rubber gasket for protection.

The oil pan has a hole in the middle where the coolant, fuel, and other fluids can pass through, but it is sealed up by the rear main seal to prevent any outside contamination.

Sometimes, the engine leak sealer fails because of a manufacturing defect or a faulty repair job. If the rear main seal leaks, the oil pan will fill up with coolant or fuel and leak out of the car’s exhaust pipe.

How to find a good oil stop leak or leak additive?

I am going to tell you how to find a good oil stop leak. There are many products on the market, but not all of them are reliable. To avoid buying low-quality oil to stop leaks in your car, there are some ways that you can use.

  1. Make sure that the product is featured on an authoritative website or reviewed by experts and professionals.
  2. Read reviews and customer feedback online and check if they’re positive or negative.
  3. Check if the product is too cheap because sometimes low-quality materials could be cheaper to produce which will make it more profitable for the company.

Do Oil Stop Leak products work on all types of cars?

There are many different types of cars on the market and sometimes it can be confusing to know which products work with what. With so much variety and options we often find ourselves asking “Do Oil Stop Leaks products work on all types of cars?”

The answer is yes, they do! All of the oil stop leak products work with all types of cars. These include diesel and petrol. However, they do not work on fuel-cell cars or battery vehicles because these do not have combustion engines and as such do not need oil seals.

What if the oil stop leak additive doesn’t work?

If this technique doesn’t work, the only way to stop the leak is to change the seal, which going to be expensive.

Most of the time when the stop leak does not work, it is because we did not use the product in the right way. You need to pour the product into your engine oil system and then add oil and finally drive for quite a while for it to work properly.

The heat generated by the motor will allow the oil stop leak product to heat up, find its way to the leak area, seal it and you should be done. But if the motor is not heated properly, then the product will not work.

What are the symptoms of a rear main seal leak?

It is important to know the symptoms of a rear main seal leak. This way you will be able to notice if your car is leaking oil and needs repairs.

The most common symptom of a rear main seal leak is an oil leak near the rear axle. You may also note drips or pools of oil collected on the ground below your car’s engine after parking it for an extended period of time.

If you see smoke coming from under your vehicle, this may also indicate that you have a seal leak in the engine compartment. Other symptoms include a burning smell and oily residue on the underside of your vehicle.

Why is my engine leaking oil?

There are many reasons why an engine might be leaking oil. One common reason is that there is a problem with one of the gaskets. This might be due to an error during installation or due to wear and tear over time. But the most common problem comes from the rear main seal leak sealer, which has overheated or simply done its time.

You may also have hit a branch and went into a deep pothole on the road and got your engine damaged.

There are several ways to stop oil leaks:

  1. Change out your old gasket for a new one;
  2. Use sealant; or
  3. Have your mechanic take care of it.

What is the cost to replace the rear main seal to stop leaks?

What you want to do is to know the rear main seal cost and then the cost of labor.

The cost for someone with little experience to do the job I would say is about $100 for seals/gaskets, maybe another $100 or so for tools.

Now, you need to count the time that you’ll be spending on the job. It can take you 5 to 10 hours. You also need to take into account that you may not put it right when you replace the old seal. If you do, you would have wasted your time, and lost the seal.

The cost to get it replaced at a garage depends on which state you are located in. However, the average price is about $1100. This is not cheap and the lowest price we got a quote was $300.

Is a rear main seal stop leak bad for the engine?

There are a few different opinions on whether a rear main seal stop leak is bad for the engine or not.

Some people say that it is not a good idea to use sealant because it can cause more damage to the engine.

Others claim that it is safe to use and can actually help fix the problem.

There is not much concrete evidence either way, so it is up to the individual to decide what they think is best for their car.

Ultimately, if there is a leak in the rear main seal, it needs to be fixed as soon as possible to prevent further damage.

Final words

In today’s world of automobiles, there are several options for the best rear main seal stop leak.

Brands vary from premium to economical, but one thing remains true – they all perform effectively in preventing leaks if used properly. Obviously, some brands perform better than others and that is why reviewed so many different products. We came up with 5 main reviews of the best oil leak sealer.

The reason behind us looking at this particular component is that it plays a major part in the engine operation. If it begins to leak, it can cause serious damage to the engine.

When you’re looking for a reliable product that will provide peace of mind, consider some of the above rear main seal stop leak products all available on the market today.

Note that we really liked the BlueDevil Rear Main Sealer. We feel it is the one oil pan gasket stop leak product that performs the best in sealing your engine leak. Obviously, all of the products can only help if the leak is small. For larger leaks, you better get the seal to be replaced, which is a substantial expense, but a necessary one.


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