Best Engine Flush of 2023 – Best Engine Cleaner Reviews

Everyone who has even the slightest experience with cars knows that the engine is what keeps the vehicle alive. Being such an important cog in this complex machinery it is expected that an engine sustains a lot of attrition and wear and tear while they are working.

One of the best ways to help them sustain such pressure and extend their lifespan is to keep them clean and well-maintained. So far the easiest way to do that is to fill the engine with an appropriate cleaner and flush out all the existing particle deposits.

But what is the best engine flush you can currently find in the stores? Let us try to find that out together.

In a Hurry? The Winner after 32 Hours of Research:

Liqui Moly Pro-Line Engine Flush | 500 ml | Oil additive | SKU: 2037

Our Rating: 95/100

Why it is the best?

  • Incredibly easy to use
  • Works on both major types of engines
  • Excellent cleaning performance
  • Good priming for an engine oil change
  • Boosts engine performance
  • Not overly expensive
  • Amazon bestseller
  • Great customer feedback

How I Picked:

16 Resources 

188 Reviews Compared

32 Hours Of Research 

24 Popular Products Considered

Last Updated: June 09, 2021

By James Ruhle: This article has been updated to reflect the most accurate information regarding best engine flush available for those who are interested in enhancing their engine. The best 5 available have changed, and information has been added to assist individuals in finding the best engine flushers currently available on the market. The FAQ has also been updated.

Current Top Fuel Stabilizers On The Market- Comparison Table


Type Of Engine

Package Size

Our Rating

Current Price

Liqui Moly Pro-Line Engine Flush | 500 ml | Oil additive | SKU: 2037

Gas and diesel

17 Ounces


Lubegard 95030 Engine Flush, 15 oz.

Gas and diesel

15 Ounces


Prolong Super Lubricants PSL11000 Engine Treatment - 12 oz. , White

Gas and diesel

12 Ounces


Golden Touch 1698 Fast Flush Engine Flush - 128 fl. oz.

Gas Only

128 Ounces


Energy Release P023 Motor Flush - 15 fl. oz.

Gas and diesel

15 Ounces


Sea Foam SF-16 Motor Treatment - 16 oz. , white

Gas and diesel

16 Ounces


STP High Milage Engine Flush Formula, Oil Cleaner for Cars and Truck, 15 Oz

Gas Only

15 Ounces


Niteo Motor Medic MF3 5-Minute Motor Flush - 32 oz, Multicolor

Gas and diesel

32 Ounces


Best Engine Flush Buyers Guide

The grades above were the overall impressions of the products I am going to discuss in greater depth further down below. But, what criteria I used to rank them? Or even better, what makes a good engine cleaner in the first place?

These things are hard to answer. You see, the engine flushes I prefer may not necessarily suit your vehicle and fit your budget. That is why I comprised this short buying guide that will help you find your ideal pick in case you don't agree with my choices.

Here a couple of things to take into consideration before buying an engine flush.

The type of engine flush additives

When it comes to engine flushing and particle buildup prevention, there are many additives available within a range of formulas. While their overall goal is the same, each formula has unique features that offer various levels of performance depending on your needs.

The additives themselves can be divided into five major groups:

  • Detergents - This additive is the major ingredient responsible for dissolving accumulated motor sludge. Usually, they are based on alcohol and acids.
  • Dispersants - Essentially, the role of dispersants is to break up solidified carbon deposits. They are necessary for cleaning hard-to-reach areas like the power system.
  • Antiwear - One of the most common non-essential additives. What antiwear does is to use some type of metal to bond the materials in the engine and prevent future wear and tear. If you are looking to get this type of remedy keep in mind that these agents work best when combined with harsh detergents.
  • Lubricants - The main purpose of the lubricants is to reinforce new oil used after the engine is flushed, thus extending the mileage of the oil.
  • Rust inhibitors - This additive is not as common as previous mentions but you can find it a lot of famous products out there. As you can guess its primary purpose is to prevent corrosion of the material. But due to their specific formula, they work well only when put in milder engine flushes.

Depending on the state of your vehicle's engine, you should choose the product that features one or several of these important ingredients.

Type of the engine flush

In this case, the rules are very simple. In other words, the engine flushes, in broad strokes, are dived by the type of the engine they are designed to service. Still, here is a short breakdown:

  • Gasoline engine flush - So, you get the idea of which type of vehicles you should use this group. You should, however, know that some of the products in this category are designed for fast-reacting time or vehicles with high mileage.
  • Diesel engine flush - Due to the specific nature of this type of motor (and fuel for that matter). the diesel engine flushes are usually engineered to double down on removing the gunk that builds up inside the unit. In other words, they are harsh and potent.
  • Gasoline and diesel engine flushes - These products are all about convenience. However, the novelty of not having to worry about the engine type often comes at the cost of convenience.

Ease of use

If you're looking to freshen up your engine, a wide selection of flushes is available for use without specialized tools or extensive knowledge. But if you'd prefer a more thorough cleanse and have the time on your hands plus some mechanical know-how – special products requiring particular tools may be just what's needed! Consider both options carefully before making that final decision.


When looking for an engine flush, it's important to do your due diligence as some products may not be compatible with certain types of engines. Modern car models contain complex components made from different materials that can easily be damaged by acid-based ingredients in the formula - so always consult the vehicle manual to ensure you select a safe and suitable product!

Of course, we could count the price of the package, size of the bottle, and similar things as important considerations as well. But, all these things are more concerned with your maintenance habits so I won't elaborate too much on them. You get the idea.

Best Engine Flush Products On The Market- Individual Reviews

Liqui Moly Pro-Line Engine Flush | 500 ml | Oil additive | SKU: 2037

Our Rating: 95/100

When it comes to popular engine flushes, Liqui Moly comes as close to perfection as it gets. After the extended testing of this package I can say that 2037 Pro-Line flush lives up to the expectations I have from this famous brand and easily makes one of the best entries on the list.

So, what makes this engine flush so special?

Make oil changes easier with this product! In just three simple steps, you can keep your car running smoothly: remove the motor oil cap and turn on the engine for 15 minutes to circulate the flush through. Finally, open up that final flush sealer - no more stress or hassle involved in keeping your vehicle taken care of.

The second thing I like is that the formula can be used both on gasoline and diesel engines. But, this versatility doesn't come at the cost of efficiency. On the contrary, although the additives used in the mix are very gentle they are productive, so I didn't have any problem removing all sorts of greases and sludge in the vehicles I used for testing.

At the same time, the flush was tame enough to leave the various non-metallic parts like seals entirely undamaged. Believe me, formulas that are as balanced as this one are not that easy to find.

What did I get after I flushed the engine and performed oil change?

Recent advancements in oil consumption and fuel economy have revolutionized how we drive. Not only are cars quieter, but they also accelerate more easily when going up inclines – just two of the many benefits seen from this incredible progress. Without a doubt, these developments bring about sure satisfaction for drivers everywhere!

Are there any drawbacks? Sure, but in this case, they are not truly deal-breakers.

This product may boast an excellent blend of additives, but it's not recommended to use it on aged engines that have built up dirt and grime. Trying to break down these deposits with this bottle could leave you stranded at the mechanic rather than back out onto the roads again!

Also, we can't escape the feeling that, in spite of great performance, the bottle is still too pricey for a wast majority of car owners. If you can live with these two things, give it a try - you won't regret it.


  • Efficient and versatile performance
  • Very easy to use
  • Improves engine performance
  • Neutral to sensitive parts


  • Not suitable for older engines

Lubegard 95030 Engine Flush, 15 oz.

Our Rating: 90/100

Lubeguard is yet another famous brand on this list so you can only guess just how excited we were to test their latest motor flush. Much like in the case of Liqui Moly 2037 Pro-Line Engine Flush very pleased with the overall results. Unfortunately, not as pleased. The difference was marginal but we were still able to take notice.

But, let's not get ahead of ourselves.

Lubegard 95030 Engine Flush is formulated with a special blend of additives that effectively break down stubborn gums, varnishes, and sludge while being gentle enough to preserve critical seals and gaskets. Offering both gas engine compatibility as well as diesel engine useability, this useful lubricant is easy-to-use without compromising the health or longevity of your car's components.

And once again, the flush is extremely easy to use. The only thing you need to do before you drain the oil is to pour down the liquid into the engine and keep the car running for a couple of minutes. Although the manufacturer claims you can get away with 5-10, we advise that you go with standard 15 minutes treatment for the best possible results.

And what can we say about results?

After engine flushing with this product, you can expect a smooth and quiet ride for your car-- almost equivalent to the performance achieved by Liqui Moly. Although fuel economy may not be drastically improved, there will still be an overall reduction in oil consumption.

So, this product is definitely oriented more towards proper maintenance rather than optimizing engine performance.

Although some minor issues come with this product, such as an expensive price tag and occasional compatibility problems between the older engine system and its multi-type features, these can be easily overlooked for all of the advantages it offers.

Use it at your own responsibility.

So, we can't resist but to recommend this product. You won't be disappointed as long as you don't expect noticeable engine performance improvement. As far as cleaning and maintenance go - it's great.


  • Great cleaning properties
  • Very user-friendly
  • Removes sludge and deposits


  • Doesn't improve car performance
  • Slightly expensive

Prolong Super Lubricants PSL11000 Engine Treatment - 12 oz. , White

Our Rating: 95/100

With outstanding customer reviews, Prolong Super's engine flush is a great option to consider when looking for an effective yet affordable solution. Not only will you get the same performance as with pricier offerings but also benefit from its cost-effective price point.

So, once again we have a formula that was engineered to work with metallic surfaces of gas and diesel engines. According to the manufacturer, the product features a specially devised formula that doubles-down on anti-friction properties and helps molecules to bond and create a new protective layer on the parts within the engine.

So, if you are looking for antiwear properties, this bottle is definitely for you.

If you're looking for a hassle-free experience that can help take care of your oil change and engine flush, our one-step procedure found in the FAQ section is an ideal choice. From what we've seen, older cars stand to benefit significantly from this method as far improvements with fuel economy are concerned.

With minimal effort on your part, you could soon find yourself enjoying many more miles per gallon!

Namely, the oil consumption on tested vehicles became drastically lower. We also felt the cars were running more smoothly on all types of terrain and finally, the rattle on the startup was as good as gone. And we are talking about a couple of vehicles we used for testing.

And the fact that the engine flush works with worn-out vehicles deserves praise on its own.

So we can't help giving this neat product a credit where credit is due.

Despite the engine flush's potential to improve a vehicle's overall performance, its cost may be prohibitive for many drivers of older cars. Consequently, this product might not suit everyone looking to maintain their car’s longevity and reliability without breaking the bank.

The other complaint is that the results are nowhere near as good when we move to newer car models. Still, cleaning properties are rock-solid.


  • Works like a charm on older engines
  • Excellent cleaning properties
  • User-friendly
  • You can use it on both types of engines


  • Expensive
  • You can find more affordable alternatives

Golden Touch 1698 Fast Flush Engine Flush - 128 fl. oz.

Our Rating: 92/100

Now, this product is the polar opposite of the previous engine flush I have just covered. Oh, don't get me wrong, this flush also asks you to pay a very steep price. But, as a consolation prize, you do get one huge (128 ounces) bottle to play with.

But, let's start at the beginning.

This powerful product is specially tailored to optimize performance for both domestic and imported gas engines. With the manufacturer's expertise, they have designed a formula that enhances engine capabilities like never before.

So, what we have here is a petroleum-based flush that does not contain any ingredients like kerosene and mineral spirits that could potentially damage some parts of the engine, but does an incredibly satisfying job when it comes to cleaning and maintenance.

What do I mean by that?

Well, the product is very user-friendly and you won't need any help pouring the liquid before the oil change. Of course, as long as you are able to get around the size of the bottle. Repackaging the liquid into a couple of smaller bottles will definitely make this job far easier.

But, the main point is that this engine flush does a pretty good job at removing varnish, sludge, and deposits built up within the engine. But, this is the furthest this product manages to go. If you expect your old car will start flying after a single treatment. If you have to get the optimal results you need to play a long-term game and put a lot of care into engine maintenance.

Forget miracles - this engine flush may be affordable but it has all you need to keep your vehicle's engine cleaning and running smoothly! Sludge can easily accumulate and cause problems, so why waste money on more expensive solutions? Invest in a budget-friendly option that'll get the job done right.

If I was doing some ranking by categories this would definitely be one of the best budget picks.


  • Excellent budget pick
  • Ample package
  • Good long-term performance boosts


  • Lacks immediate results

Energy Release P023 Motor Flush - 15 fl. oz.

Our Rating: 93/100

Energy Release 9023 Motor Flush is yet another engine flush with an incredibly lucrative price tag. How lucrative? Well, I can say that for the price of one Liqui Moly, my overall winner of the roundup, you can easily buy two of these bottles. And, just for the reminder, the first product I have reviewed is not even the most expensive on the list.

This diesel and gas engine flush is a reliable, all-around compound that attacks sludge while protecting delicate surfaces. Its balanced formula may not deliver dramatic results in newer cars, but many older engines will benefit from its performance boost. Whether your vehicle has been on the road for years or just hit the pavement yesterday - this product offers an affordable yet effective solution to keep it running smoothly at peak efficiency!

One of the reasons behind this is that the engine flush contains anti-friction lubricant additives that don't make that much difference in newer units but do help worn out machines run faster. 

When I applied this liquid and performed the oil change, the change in performance was more than noticeable.

Despite its low price, this engine flush may not be effective for newer car models. There is a risk of compromising performance when using "one-size-fits-all" products designed to work with many types of vehicles. Ultimately, it's important to weigh the cost versus the benefit before investing in an engine flush product.

I would also say that the claims by the manufacturer that the engine flush increases horsepower and fuel efficiency are, to a large extent, misleading.

Be that as it may, this is by far one of the best engine flushes we have found in this price segment and can't offer anything but recommendations. If you own an older vehicle or like to change motor oil frequently so you can't afford a more expensive engine flush this is the product you are looking for.

Just make sure you know what you're buying.


  • Extremely affordable
  • Works well on older engines
  • Lubricative properties


  • Mild overall performance

Sea Foam SF-16 Motor Treatment - 16 oz. , white

Our Rating: 91/100

Sea Foam SF-16 Motor Treatment is yet another engine flush that tries to sway customers with an affordable price tag. But, as we all saw from a previous couple of reviews, high-quality compounds are not that uncommon even when you go down to the very bottom of the price ladder.

So, how does this engine flush bodes against this harsh competition?

The engine flush tested well and is a solid choice for customers within its price range. It does not, however, promise superior performance when it comes to boosting the life of engines; rather it excels in cleaning properties with both major types compatible. All-in-all this product offers guaranteed satisfaction without too much hassle or stress on your wallet.

By that, I mean that you can easily use the product without anyone's help and since you are done with the oil change, the motor, injectors, cylinders and other parts of the fuel system should be devoid of less stubborn residue and sludge particles.

And to be quite honest, I have to admit that I was able to get slightly more mileage out of the motor oil. But that is how far this engine flush is able to reach. If you expect your car to run faster, work more silently, or squeeze out more horsepower, you will be left disappointed.

Bottom line - this is one decent engine flush that does provide reasonably competent maintenance performance and packs one very strong price-value ratio. If you are satisfied with that, give it a try.

But, keep in mind that you can find a couple of better engine flushes in this price range.


  • Very affordable engine flush
  • Solid cleaning properties
  • Spacious bottle (18 ounces)


  • Mild overall performance

STP High Milage Engine Flush Formula, Oil Cleaner for Cars and Truck, 15 Oz

Our Rating: 89/100

On this list, I have already covered a couple of products that offered more than capable performance when it comes to older vehicles. This, however, is the first engine flush of the roundup that is aimed at owners of the vehicles with more than 75,000 miles under their wheels.

The problem with this one, though, is that while these previous engine flushes did offer reasonable performance upgrades when applied to older engines, in this case, the results are very mild. Let me explain what I mean by that.

STP High Mileage Engine Flush Formula is an outstanding way to reduce sludge and varnish from your engine's cylinder heads. After use, you'll be as close to having a factory-fresh vehicle - no matter how much mileage it has! Plus, the price of this product offers excellent value for money: not too cheap so that its quality suffers; but also neither overly expensive nor scarce in size.

With 15 ounces on disposal, you will get more than enough liquid to properly clean the vehicle that has been neglected for years.

Although reasonably strong, the liquid won't damage any sensitive parts and will prime the engine for a fresh batch of engine oil.

With this engine flush, you can expect to avoid potential problems down the road. However, it shouldn't be used as a magic bullet for improving performance in older vehicles; while they may become notably cleaner and smoother running over time with regular use of such additives – don’t anticipate your vehicle becoming completely transformed!

So, to sum it all up, this engine flush doesn't do anything particularly wrong and there is no danger you will accidentally damage the machinery. But, on the other hand, the results you are going to produce will remain forever tame so there isn't something to write home about, either. Make sure to take all this into consideration before buying.


  • Reasonably affordable
  • Efficiently cleans older engines
  • Ample size of the package


  • Performance boosts are all but absent

Niteo Motor Medic MF3 5-Minute Motor Flush - 32 oz, Multicolor

Our Rating: 80/100

Last but not least, we have Niteo Motor Medic MF35, an engine flush that sits somewhere in the upper areas of this product range. Well, at least when it comes to the price. This engine flush would get far more favorable reviews if it was sold under the $10 mark. As a silver lining, you do get a lot of liquid for the price you pay. But, the flush features some stiff competition even in this regard.

Motor Medic's engine flush stands out in the market due to its fast-acting results - just 5-10 minutes of running your engine produce desirable effects. Additionally, this product optimizes motor oil usage and works on all types of engines including non-turbo, turbo, and diesel with guaranteed safety for sensitive parts like gaskets. This an ideal solution for those seeking an efficient way to maintain their car’s performance!

While Motor Medic's engine flush provides an effective clean of your motor oil, similarly priced brands offer superior performance comparison. With the price-value ratio taken into consideration, this product may be considered tame when stacked up against other options on the market.

So this is pretty far the best engine flush you can find in the market at the moment. But, you do get solid cleaning results. That would earn our recommendation if not for the hefty price. This way, the only thing we can say is you can find far better alternatives.


  • Good cleaning properties
  • Fast-acting time
  • Works in all types of engines


  • Vert tame overall results

Best Engine Flush Frequently Asked Questions

What is the best way to clean sludge out of an engine?

In order to clean sludge out of the engine of your vehicle, you will need to use some of the engine flush products we have listed above. But, in terms of how to perform this task as easy and effortless as possible, here are steps you should take:

  • Remove the oil filter
  • Treat the motor with engine flush (pour it down the open hood)
  • Close the hood, start the car and let it run idle for 15 minutes
  • Turn off the engine and flush engine oil (remove the drain plug)
  • Install a new oil filter
  • Pour in fresh oil

And this is how to use an engine flush.

Will engine flush damage engine?

The short answer is no, but only as long you use an engine flush properly. What does that mean? First, a flush is not something you should use while driving. The agents will make the engine oil too thin. So, use these products only before replacing the oil.

Second, you need to carefully select the product type appropriate for the type of your engine. For instance, even if you buy the flush engineered for the appropriate type of engine, some formulas may prove to be too potent and abrasive for older units. If you are in doubt, ask your mechanic for advice.

How much engine flush should I use?

Whether you need one or two bottles of oil flush depends on the product and your engine size. Fortunately, the manufacturer will always provide usage guidelines printed on the back of each package - so don't forget to read through it carefully! In general, engines up to 10 quarts call for a single bottle while larger capacities require an additional dose.

After it's all said and done, we recommend:

As we already mentioned in the previous sections our pick for the title of the best engine flush on the market is without any doubt Liqui Moly 2037 Pro-Line Engine Flush. Sure, you are asked to pay a couple of dollars above the average. But, the price is still far from outrageous. What you get for this money is excellent motor cleaning, good priming for an engine oil change, and a noticeable vehicle performance boost. In our opinion that warrants the price.

After It's All Said and Done, I Recommend:

Liqui Moly Pro-Line Engine Flush | 500 ml | Oil additive | SKU: 2037

Our Rating: 95/100

Why it is the best?

  • This product comes from one of the most trusted brands available on the market
  • Works on both major types of engines
  • Excellent cleaning performance
  • Good priming for an engine oil change
  • Boosts engine performance
  • Not overly expensive
  • Amazon bestseller
  • Great customer feedback


So, we are finally at the very end of our short competition for the title of the best engine flush on the market. We hope the reviews were helpful. But, the best thing you can take away from this short read is that your vehicle's engine needs cleaning and maintenance just like any other part. Make sure to take this duty seriously. Using any of the engine flushes we have listed above is better than using none.

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