The Best Engine Flush 2021

An engine flush is designed to dissolve harmful deposits and maintain efficient oil circulation throughout the engine. It’s the best way to prepare your engine for fresh oil and below you can find some of our top recommendations.

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Best Engine Flush
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The best engine flush is the Liqui Moly 1019, which is a concentrated detergent formula that’s highly effective and produces a noticeable difference after a single application. If you require a more affordable alternative that’s also produced by a reputable brand, the STP GST is the best option.

Engine Flush Comparison

Engine FlushTreatsBottle
Liqui Moly 10195 Litres500 ml
STP GST3-6 Litres450 ml
Forte Advanced5 Litres400 ml
Wynns 512653-6 Litres425 ml
Comma X-Flow5 Litres5,000 ml
SYPRIN Original5 Litres250 ml

Below is a list of the best engine flush products that blend with the oil and circulate throughout the engine to remove any harmful deposits.

The Best Engine Flush


1. Liqui Moly 1019 Engine Clean

Liqui Moly 1019 Engine Clean
Liqui Moly are a highly reputable brand and their Motor Clean is one of their most rated products. It’s an effective engine cleaning additive that dissolves sludge and varnish-like pollution and is suitable for all petrol or diesel engines.

Other features of the Liqui Moly Motor Clean include:

  • Concentrated detergent
  • Compatible with diesel and petrol engines
  • Tested for turbo and catalytic converters
  • Made in Germany
  • 500 ml bottle

Although more expensive than some of the alternative, the Motor Clean by Liqui Moly is one of the best engine flush products on the market. It’s made in Germany by the reputable brand and the highly effective formula produces instant results that you will notice straightaway.
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2. STP GST Engine Flush

STP GST Engine Flush
The STP brand are well-known for their affordable yet high quality additives and their engine flush is a great example. It’s suitable for both petrol and diesel engines and is designed to neutralise any harmful acids within the engine.

Other features of the STP Engine Flush include:

  • Removes harmful sludge and deposits
  • Provides protection after flushing
  • Helps prevent minor oil leaks
  • Best used every oil change
  • Made in the UK

The STP Engine Flush is a great choice that treats 3 to 6 litres of oil per bottle and helps maintain cleanliness and performance of all your vital parts. Unlike other cheap formulas, this engine flush is backed by the reputable brand for complete peace of mind.
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3. Forte Advanced Motor Flush

Forte Advanced Motor Flush
The Forte Advanced is another premium engine flush that’s designed to keep new oil cleaner for longer. This is made possible by a recently improved formula that features added anti-wear protection additives.

Other features of the Forte Advanced include:

  • Stabilises cylinder compression
  • Provides anti-wear protection
  • Removes lacquer, varnish, sludge and other deposits
  • Frees sticking valve timing systems, hydraulic lifters and rings
  • Easy pour 400 ml bottle
  • Made in the UK

Overall, the Forte Advanced is an excellent all-round option that’s effective, manufactured by a reputable brand and is easy to use. The only minor drawback is the price but it’s a worthwhile investment that you won’t regret.
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4. Wynn’s 51265 Engine Flush

Wyn's Engine Flush
Wynn’s are a reputable brand known for their fuel injector cleaners but they also produce a variety of other cleaning additives such as their engine flush. Unlike some of the alternatives that are suitable for just engines, this particular formula can also be used for hydraulic systems, gearboxes and even differentials.

Other features of the Wynn’s Engine Flush include:

  • Frees sticking internal components
  • Neutralizes acids and provides extra protection
  • Prevents contamination of fresh oil
  • Highly concentrated detergent formula
  • Compatible with all types of oil

Overall, the Wynn’s Engine Flush ticks all the boxes and does exactly what it sets out to do on the bottle. Unlike many of the alternatives, it can also be used on a wide range of other automotive components too.
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5. Comma X-Flow Flush Out

Comma X-Flow Flush Out
The Comma X-Flow Flush Out is a premium option that promises highly effective results and is worth paying the extra for. It comes in a large 5 litre bottle that you simply pour into the engine (around half of its normal capacity) and allow to get to work whilst idling for 10 minutes.

Other features of the Comma X-Flow include:

  • Made in the UK
  • Removes sludge and carbon deposits
  • Suitable for petrol and diesel cars
  • 5 litre bottle

Although expensive, the Comma X-Flow Flush Out is a highly rated engine flush that won’t disappoint. After a single application, you should notice that you engine is noticeably smoother and quieter than it was prior to the oil change.
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6. SYPRIN Engine Oil Flush

SYPRIN Engine Oil Flush
Another German made formula that’s highly rated is the SYPRIN Original, which is suitable for the majority of petrol or diesel engines. The 250 ml bottle is enough to treat up to 5 litres of oil and it takes just 10 to 15 minutes to get to work.

Other features of the SYPRIN Original include:

  • Compatible with petrol and diesel engines
  • Cleans and maintains the entire engine
  • Made in Germany
  • 250 ml bottle

Overall, the SYPRIN Original Engine Flush is a great choice that’s been tested and proven to work on a wide range of engines. Simply pour it in, wait between 10 to 15 minutes and then replace with fresh oil.
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Conclusion

The cleaner an engine is, the more efficient it’s going to be in the long run. The engine can become clogged with harmful deposits fairly quickly and it will be have to work harder to maintain performance, which contributes to wear and tear. However, with the use of one of the recommendations above, you can easily remove the deposits prior to replacing the engine oil. For the best results, we strongly advise allowing the formula to blend with the oil and circulates throughout the engine for the specified amount of time stated on the bottle.

author dan 4car

Written By Dan

Dan has been a car enthusiast ever since he can remember and has an extensive range of cars that include classic cars that he has restored himself from a barn find condition to modern performance cars. Whether you need advice on how to install car parts or recommendations on what products to buy, Dan’s first-hand experience will certainly help.

If you want to find out more about Dan, our testing process or the website itself, visit our about page for further information.

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