Best Engine Flush – A Buyer’s Guide and Reviews

Your car’s engine is the powerhouse to almost everything. Once started, it allows fluids to move through the car and, of course, gets it on the road. And this means it needs a lot of attention.

Oil changes, injector cleanings, and spark plug replacements are definitely ways to keep the engine at peak performance. But another way is to clean out the gunk that collects inside it over time. The way to achieve this is through an engine flush.

What is Engine Flush Used For?

This procedure is the best way to eliminate old engine oil residue from all components. Though getting the oil changed helps, it doesn’t help clean the components. Thus, residue, gum, and varnish accumulate over time. By performing an engine flush, the result is a clean unit ready for a new layer of lubrication. In turn, drivers can see an increase in performance and fuel economy.

If you have never done this, then you need to know something about the best engine flush products out there. We’re here to help you with a buyer’s guide and reviews.

As you go through, be aware that the best engine flush cleaner for one vehicle may not be right for yours. If you are unsure, you should consult your user manual or dealer to determine the right one for you.

The Best Engine Flush for Cars in 2020

Throttle Muscle TM5646

The Best Engine Flush Product out there is Throttle Muscle’s Engine Scrub. Its concentrated mixture is not just a solvent to break up oil deposits, it also contains an engine oil base and solubilizer.

In simple terms, a solubilizer is an emulsifier that incorporates one phase of a product into another. In the case of this engine flush, it adds a residue cleaner to the oil base for a complete cleaning of the crankcase.

The best way to use Throttle Muscle is to add it to old engine oil prior to a change. No revving is required to incorporate this into the engine. All that’s needed is five minutes running on idle.

Most of the reviews on Throttle Muscle Engine Scrub are positive. In addition to its engine cleaning qualities, it can also clean the engine’s internal sensors and turn off any previous error codes. Reviewers are also impressed by the oil’s clear color once it’s added into the engine, and happy with the smoother performance.

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Niteo Motor Medic MF3 5-Minute Motor Flush

Sometimes, you need more flush to remove oil residue. Perhaps it’s an older engine. Or perhaps you have purchased a car that doesn’t have a concrete service record. If this is the case, go with Niteo Motor Medic.

This is a 32 oz. container for use with the above engines or for more than one vehicle. It’s also an all-purpose flush that does more than clean out old oil.

This performance-grade liquid eliminates accumulated varnishes and gums from internal parts. When this occurs, this product helps them to release sticky valves and piston rings. Once the filter is replaced it increases the free circulation of new oil to all parts of the motor.

Like Throttle Muscle, it takes Motor Medic five minutes in idle to clean the engine once applied. Therefore, it should be used right before you change the oil. You should never drive your vehicle with the product still in the engine. So if taking it to a shop, make sure you add it once you arrive and sit in idle before it’s brought in.

The reviews for Motor Medic are overwhelmingly positive. Users are impressed with how well it thins the oil out once the engine has idled for five minutes. Others use it with older cars with questionable maintenance histories. Many reveal the flush helped to reduce or eliminate tapping and ticking noises.

If there are any negative reviews on Motor Medic, they are from users with vehicles that have over 75k miles on them. Instructions suggest removing the oil pan to clean it out. This can be a non-starter for those who have never changed their own oil.

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Lubegard 95030

Though slightly more expensive than the first two flushes mentioned, Lubegard 95030 still comes highly regarded. There are a few reasons for this.

Firstly is its multi-purpose use. Many engine flushes are only used for standard gasoline engines. If a diesel or turbo engine requires cleaning, manufacturers direct consumers to their other products.

This isn’t the case with Lubegard 95030. It works not only for standard gas engines but diesels as well. This is a huge advantage to a consumer as some diesel-only cleaners are more expensive.

Secondly is how the product is made. Some flushes include solvents that not only clean but also can cause potential damage to seals and gaskets. In the end, while their engine may be clean, it won’t start due to corroded components.

Lubegard 95030 doesn’t use harmful solvents. The synthetic blend contains non-toxic detergents and dispersants to remove accumulated varnishes, sludge, and combustion by-products. Thus, the engine is ready for oil replacement and enhanced performance without the potential for damage.

The third reason for its higher price is the level of contaminants it removes. Standard oil filters normally remove these compounds up to 25 millionths of a meter, also known as a micron. However, the most damaging contaminants to a motor are at levels between 5-20 microns.

Overall, this means your engine is constantly at risk from increased wear. And it’s not just the motor. These contaminants also continue to circulate in the oil pump and pan. So new oil quickly becomes dirty within a shorter period of time.

What Lubegard 95030 does with its bio-tech protectant is get down to those 5-20 micron levels to remove all remnants of varnish, sludge and other contaminants. This increases the engine’s performance and lowers temperatures to keep everything running at top performance. All it takes is one 15 oz. bottle and an idle time between five and 10 minutes.

One of the pros with this product is its use in high mileage motors. No need to remove the oil pan with these models. Lubegard thins the oil and contaminants enough that a simple drain and new filter does the job.

Another positive review mentions how long it takes for new oil to darken – around a couple of weeks, by which time, Lubegard can be used for another oil change.

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Liqui Moly 2037 Pro-Line

There are many positive reviews connected to this flush. It’s a very simple and useful detergent and solvent for dirty engines.

For use in either gasoline or diesel engines, Liqui Moly provides a gentle cleaning that doesn’t cause damage to internal components or other connected parts such as the oil pump or catalytic converter.

It isolates contaminates in the form of liquid or solid particles and it does this with 10 minutes of idle time. Once clean and new oil is added, it improves engine performance and shields against corrosion of unprotected metal surfaces.

What many reviewers like about Liqui Moly is its use in older high-mileage engines. Some vehicle owners have used it on motors with 300k miles or more. After an oil change, they are amazed at their increased performance.

Those who did not like the product attributed it to not improving performance after application.

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Sea Foam Extreme Marine

Don’t let the product name fool you. Though this motor treatment can be used for marine vehicles it is also used by many for standard autos. And not just personal cars, as it is designed for both gasoline and diesel motors, the flush is also used for fleet vehicles, like semi-trucks.

Sea Foam is made from 100 percent pure petroleum and is EPA registered. Like others on this list, it removes contaminants, varnish deposits, and gum build up from engines. However, as they say on game shows … Wait! There’s more!

This product cleans fuel injectors and carburetor jets. It cleans and lubricates pistons, cylinders, and intake valves. And it can clean timing chain tensioners and Variable Valve Timing (VVT) actuators to quieten down noisy areas.

In other words, Sea Foam is an all-in-one product for enhanced engine performance.

Positive reviews run the gamut. Some are happy that it can be used for fuel-injected motorcycle motors. Others are pleased with an increase of fuel efficiency after using the treatment.

As to the cons, reviewers believe the price of Sea Foam is too high (though, it is less expensive than other flushes on this list). Some recorded negative reviews because of after-treatment issues. For example, one user said their engine light turned on after use and an oil change, while another vehicle owner said it caused damage to their fuel pump.

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Lubegard 40902 Bio/Tech Engine Oil Protectant

This Lubegard product can be used in conjunction with the Lubegard 95030 flush or on its own.

If used after a flush and oil change, the treatment has the maximum effect to optimize engine power and reduce wear. If not, it will still optimize but not in the same capacity.

In either situation, this engine oil treatment will increase horsepower in both gasoline and diesel engines as well as improve fuel economy. As it does this, it also protects and extends the oil’s life by about 30%. It does this via its anti-friction and anti-wear properties.

When used after a flush, it doubles the protection on metal components to increase their lives. In addition, it eliminates noises on startup during both normal and cold weather conditions.

The other advantage of this Lubegard product is temperature reduction in hot engine oil. Not only does this help engines run smoother but also curbs oxidation around engine components.

How is this all done? Through the process of Liquid Wax Ester (LXE) technology. This element increases or adds anti-wear agents and anti-corrosion compounds to new oil to help shield engines from further buildup or damage. Furthermore, it keeps them active even when the elements in the oil become depleted.

Overall, reviewers are impressed with the science behind this Lubegard product. It’s not a “snake Oil additive” as others advertise. Some have reported new oil that is four percent cooler.

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Prolong Super Lubricants PSL11202 Engine Treatment

Out of all the flushes reviewed, this is the most expensive, mainly due to the volume. It comes in a one gallon container.

The other is the science behind the treatment. Prolong features anti-friction metal treatment technology. Molecules within the product chemically bond to metal surfaces to create a protective layer. Therefore, it is shielded from damage due to friction or heat.

Another feature of the Prolong formula is that it doesn’t contain solid particles in the form of PTFE resins or graphite. In other words, it comes as natural as possible to protect the engine even when new oil isn’t fully circulating.

The treatment is also effective under extreme pressures where metal-to-metal contact occurs the most. In these situations, motor oil is squeezed out, therefore those areas lose lubrication and start to heat up. Because Prolong adheres to metal surfaces, this friction is minimized or eliminated as new oil surrounds the parts.

A high percentage of reviewers give Prolong excellent marks. Some have used their products for 25 years with positive results. Others are impressed with its use in fleet vehicles that run on diesel engines.

Not only can this treatment be used in personal and fleet vehicles but also on marine transportation with standard gasoline or diesel engines. Those who have used it on boats have seen a significant drop in engine temperatures one they added Prolong to their oil.

And then there are reviewers who say the Prolong engine treatment helped them get their vehicles to the shop when something had broken. For instance, one commenter revealed the use of the treatment allowed them to get their car in for service when their radiator hose burst. Prolong kept the engine temperature cool enough to allow this to happen.

The most common con about the Prolong treatment is consumers can’t tell if it is working or not. In many of these reviews, the drivers decide to be patient to see what happens. Another con from a long-time user is Prolong’s change in formula. They feel it’s now too thin and runny to do the same job as it previously did.

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There you have it. A comprehensive list of the best engine flushes on the market today. The choice can be a difficult one. What you need to consider is the type of engine you have and how many miles it has been driven.

Some agents, like Throttle Muscle only work on standard gasoline engines and not diesels. So, if your vehicle is turbocharged or your big rig needs a cleaning, then you may need to seek out another product. Many of those listed after Throttle Muscle service both traditional and diesel engines.

Another thing to consider is mileage. Some of the ones listed may work better in newer engines than in older models with 75k miles or more. If you have a vehicle with a long-running engine, or if you’re unsure when it was last serviced, purchase a treatment that works with motors of all ages.

Here are some other things to consider when determining the best way to flush engine oil.

Read the directions – Don’t pour anything into your engine without reading the product directions. As we mentioned above, some products want you to remove oil pans to clean out accumulated gunk that is dispersed once the treatment is used. If you are not a hands-on vehicle owner, then it’s best to choose another product.

Do not drive your vehicle with flush liquid – Flushes and treatments can be two separate things. Treatments provide an extra layer of security once the flush is complete. Think of it as an additive like a fuel injector cleaner. So, once applied, it can still be driven.

Flushes break down treatments and other components to thin out the oil. So if you drive to the local shop for an oil change, the liquid in your engine won’t have the viscosity to shield engine parts. The result is higher temperatures and increased friction on metal surfaces.

If the manufacturer says to idle the vehicle for a certain amount of time, then do so. Don’t think it will be okay to drive the short distance to the shop. Those few miles can do more damage to your engine than the accumulated oil deposits.

Be patient – Some reviewers of these flushes and treatments gave them poor marks because they didn’t see immediate results. Or, what they saw was minimal.

Like anything, you need to give the products time to work. Once an engine is completely clean, it may take some time for the new oil to circulate through all the parts and eliminate previous problems. Same goes with a treatment.

If they don’t help, no matter how many times used, there might be another issue with the engine or its components that needs to be addressed. At that point, have a service technician examine the areas for any potential repairs or replacements. Once done, you may finally see a performance increase with flushes and treatments.