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After a while, your engine may start accumulating sludge and deposits that can adversely affect your vehicle’s power and performance. These contaminants can clog oil passages, restrict oil flow, cause rings to stick, and generally reduce compression and horsepower. If you want to eliminate this unwanted gunk, you can use an aftermarket engine flush.
Simply pour it into the oil filler so it will circulate through the engine and remove deposits. Then you drain the oil, which should be full of the harmful deposits, swap out the oil filter, and add new oil. Many types of engine flush products are available online and in stores, so it can be tough to choose the best one. Check out some of the best options in the buying guide below.
Summary List
- Best Overall: Liqui Moly 2037 Pro-Line Engine Flush
- Best Value: Sea Foam Marine and RV SF-16 Engine Flush
Also Consider
- STP 18566 High Mileage
- Bg109 Engine Performance Restoration
- Resurs Total Engine
- Motor Medic Synthetic Motor Flush
- CRC Salt Terminator
- Hapco Fast Motor Flush
- ATOMEX Total Flush
Our Methodology
We can’t put our own hands on every item available. In these instances, we put our collective experience in journalism, research, and prior product testing to use to make our product picks. Items that are used by our own staff may get earnest endorsements as well, but we’ll never accept fees or bonuses to sell you stuff we’re not actually excited about. Affiliate revenue is always disclosed.
The Drive aggregates reviews and research from all over the internet to figure out which products are worth buying. We also put out shopping guides to help you understand how to assess the value of these things on your own. As our editorial cousins at Car Bibles say, “Knowledge is horsepower!”
Best Engine Flush: Reviews & Recommendations
Best Overall
Liqui Moly 2037 Pro-Line Engine Flush
Best Value
Sea Foam Marine and RV SF-16 Engine Flush
Honorable Mention
STP 18566 High Mileage Engine Flush
Honorable Mention
Bg109 Engine Performance Restoration
Honorable Mention
Resurs Total Engine
Honorable Mention
Motor Medic Synthetic Motor Flush
Honorable Mention
CRC Salt Terminator Engine Flush
Honorable Mention
Hapco Fast Motor Flush
Honorable Mention
ATOMEX Total Flush
Our Verdict on the Best Engine Flush
Our pick for the best engine flush is the Liqui Moly 2037 Pro-Line Engine Flush. Not only is this formula quick and easy to use, but it prolongs an engine’s lifespan by effectively removing sludge and other deposits.
For a more budget-friendly option, consider the Sea Foam Marine and RV SF-16 Engine Flush.
Types of Engine Flushes
Gasoline
This type is specially formulated to work in vehicles powered by gasoline engines. There are gasoline engine flush products made for particular applications such as higher-mileage engines, as well as some designed to work as quickly as possible. The best oil flush products for gasoline engines will utilize a proprietary blend of additives to rid your engine of harmful deposits and sludge.
Diesel
If your car, truck, or SUV is powered by a diesel engine, you’ll want to only use a diesel engine flush. This type is specifically engineered to flush out the harmful carbon deposits, gunk, and sludge that build up in diesel engines over time. A common subcategory of diesel engine flush products is diesel truck or SUV flushes.
Gasoline & Diesel Engine Flush
The other common type of engine flush you’ll find on the market today is a flush formulated to work effectively in both gasoline- and diesel-powered engines. These versatile products are convenient because they can be applied to either engine type so you don’t have to worry about buying an engine flush specifically made for a gas or diesel engine.
Best Engine Flush Pricing
- Under $10: Shoppers will find a few value-priced options for under $10. These affordable products offer decent performance for a modest price and remain popular largely due to their excellent value.
- $10 – $19: Consumers will delight in the vast amount of engine flushes available in this price range. The majority of motor flush products at this price point are simple to use and deliver excellent sludge-busting performance.
- Over $19: There are just a select number of options priced above $19. Shoppers will find some of the best oil flush products around this price point, though some of the more affordable options may be just as effective but lack the brand cachet of these pricier offerings.
Key Features
Engine Type Compatibility
The most critical feature of engine flush products is engine type compatibility. Motor flushes can be compatible with gasoline or diesel engines, and in some cases, both engine types. For best results, it’s important to only use one formulated for the type of engine in your vehicle. Many consumers elect to use an engine flush treatment designed for both gasoline and diesel engines because they don’t have to worry about engine compatibility.
Solvents
Many engine oil flush products use a formula that contains solvents to assist with cleaning any carbon deposits, gunk, and sludge that accumulate in your engine. While mild solvents may be handy in clearing out sludge in high-mileage engines, most consumers will want to avoid purchasing an engine flush that contains too many solvents because they can deteriorate engine seals and gaskets.
User-Friendliness
Another prominent feature of engine flushes is the user-friendliness of the product. The majority of engine oil flushes are designed to be easy to use without the aid of an engine flush machine, but a few require the use of special tools that attach to a garden hose to flush out your engine. You’ll want to consider your mechanical skill level as well as any time constraints before selecting the right product for your needs.
Additives
An engine flush is essentially a blend of specific additives mixed into a single solution. With that said, different products contain different additive blends which are frequently engineered to deliver a specific result. The best engine flush product generally contains a mix of detergents, dispersants, anti-wear additives, lubricants, and rust inhibitors. Make sure the one you’re interested in contains at least a few of these additives for maximum cleaning power.
Other Considerations for the Best Engine Flush
- Quick Results. If time is a major factor for you when it comes to flushing your engine (and when is it not important?), you’ll want to consider an engine flush that is designed to deliver quick results. Many popular brands boast that their product works in as little as 10-15 minutes, saving you tons of time without sacrificing satisfactory results.
FAQs
You’ve got questions. The Drive has answers.
An engine flush is an aftermarket additive engineered to flush accumulated deposits, sludge, and other gunk out of your engine. You simply pour it into your engine’s oil-filler port and let your engine idle for roughly 10-15 minutes. It blends with the oil and circulates through your engine, dissolving sludge. Next, you drain the oil, change the oil filter, and add fresh oil.
One of the most common causes of carbon buildup in your engine is taking frequent short trips. If you notice your ride doesn’t feel as peppy as it usually does or if there’s a drop in fuel mileage, you may need to flush your engine. Other signs include a premature oil change light, signs of oil splatter or sludge under your hood, and sludge present in your oil pan.
Engine flush machines are great for speeding up engine flushes; however, they can be very expensive. Most drivers elect to do the job without the assistance of a machine. If you know how to change your own oil, then you possess the mechanical skills necessary to perform an engine flush job on your vehicle.
The exact time it takes to flush your engine without the aid of a machine depends on the motor flush you’re using. The best engine sludge cleaners take as little as 10 to 15 minutes for a person of modest mechanical capabilities to perform. If you’re new to the whole wrenching thing, then the whole process will obviously take slightly longer.
Most cost anywhere from $7 to $19 for a 15- or 16-ounce bottle. You’ll want to also factor in the cost of a replacement oil filter and motor oil. Most people choose to flush their engines without the aid of a professional, but if you do choose to have a mechanic perform the job, expect to pay anywhere from $100 to $150 in parts and labor.