Best Engine Flushes: Feeling Flushed

Vivek Nayyar
by Vivek Nayyar

Top 7 Best Engine Flushes

We’ll preface this post with the admonition that, unless you’re reasonably familiar with the environs of an engine bay, you should keep your paws off stuff like this. However, a case can be made that anyone who’s fleet is comprised of machines that actually need these products is probably intimately familiar with the contents of a rusty toolbox.

On one hand, additives like these have their proponents, who declare them the best thing to happen to cars since the assembly line. On the other, there is a group of skeptics who feel they’re nothing more than snake oil in a can. All we can tell you is that there are plenty of them on the market and it’s our job to suss out a few with the best reviews. And, for the love of all that’s holy, read the instructions with products like this.

Given the hooptie state of our cars around here, we may have even used one or two of these things ourselves.

Table of Contents

1. Editor's Choice: Liqui Moly Pro-Line Engine Flush

If you've ever watched any sort of racing out of Australia, you've seen plenty of ads for Liqui Moly. Despite their massive presence Down Under, they're actually a German brand with roots stretching all the way back to the 1950s. Their sole purpose for being is to hawk oils, lubricants, and additives.

Of which this is the latter, naturally. It's an engine flush marketed as an easy way to clean and flush the oil systems of gasoline or diesel mills. Neutral to seals and other materials installed in the engine, it purports to give a 'gentle and rapid cleaning' by dissolving sludge and lacquer while isolating solid particles and liquid contaminants.


  • This brand makes over 4,000 products so they know their stuff, top-notch reviews


  • You'll probably end up buying more than one item from them

Bottom Line

  • Solidly endorsed by real-world customers

2. Rislone 100QR Engine Treatment Conditioner and Cleaner

Like the Turtle Wax name we mentioned the other day, Rislone is a brand your author associates with products his father used. This is not wholly a bad thing, since each of Dad's cars lasted well over 10 years. Well, except the 1984 Renault Encore. Because Kenosha.

This bottle of wonder is apparently capable of freeing valves and lifters, something that afflicted Dad's 1978 Blazer from just about Day 1. The fact it kept running could be a testament to Rislone. The company also says this product maintains oil viscosity while dissolving and removing harmful deposits.


  • Been around forever


  • Best to buy a case of six (small bottles)

Bottom Line

  • If it was good enough for a tired 305 small block...

3. Golden Touch Fast Flush Engine Flush

We'll leave inappropriate and lewd comments about the brand name of this engine flush to the side since this editorial team is far beyond making such jokes. Actually, we aren't - but VerticalScope's lawyers are tired of cleaning up our messes. You won't be cleaning up a mess with this stuff either, since it's a petroleum-based product that is free of kerosene.

Made in America, it is said to quickly remove more engine sludge and deposits than a conventional oil change. Note well: it's good for gasoline engines, not diesels. The instructions say to drain existing oil and change the filter. Add a gallon of this product and install a clean filter. After running the engine for 5 minutes, drain the works of it out and replace the filter again. Refill the engine with approved motor oil and you're on your way.


  • Has 'for professional use' printed right on the label


  • lulz at the brand name

Bottom Line

  • A big ol' jug of golden touch

4. WYNNS Engine Flush - Petrol and Diesel

The word 'petrol' in this product's title is a dead giveaway as to the brand's origin. But here's the thing: engines don't really seem to care what country you're in, unless it's a former Bloc country which generally has twigs in its gasoline supply.

Like others on this list, the Wynn's product is promoted as able to quickly and efficiently dissolve varnish while removing sludge and other contaminants from vital engine parts. This should leave your car's engine with sparkling clean internals - certainly cleaner than your internals after a feed of British grub.


  • Good for diesels or gassers


  • Very small can

Bottom Line

  • Add prior to an oil change for best results

5. CRC Salt Terminator Engine Flush

Yes, yes - this stuff isn't technically in the same category as everything else on this list. It is, however, an engine flush ... just one of a different type. Besides, we're sure one or two of the nutty readers in our audience has a boat they use on the water.

This gear is an essential motor flush for marine engines that are operated in both saltwater and freshwater environments. It dissolves salt and leaves a protective coating to inhibit corrosion. A good many reviewers also report using it as a spray-on their boat trailers and the like to ward off the rust monster.


  • Chases away the rusties, has the word 'terminator' in its name


  • Not actually for yer car

Bottom Line

  • Captain's choice - or at least First Mate's

6. Marvel Mystery Oil

And you thought that Mystery Machine was the only thing with that name associated with Marvel (hold your vitriol-laced comments; we know it's actually Hanna-Barbera). Here we have a two-pack of additive that is said to clean and lubricate your car's fuel delivery system including carburetors.

According to the ad copy, this stuff reduces varnish and gum while preventing further build-up of the same. Valve stick and clatter should cease, while the car's engine oil should not break down in extreme temperature conditions. It probably does bust sludge as advertised but we'd cast a skeptical eye at the claims of increased MPG.


  • Dump and run, easy to keep aboard the car


  • Your mileage may vary (literally)

Bottom Line

  • Worth a shot for 10 bucks

7. Energy Release Motor Flush

While the name of this brand might make one think it competes with the likes of Monster and Red Bull, it's actually an engine flush similar to the majority of other items on this list. It, too, promotes itself as able to dissolve sludge and wash away its buildup. Again, we'll question the claims of improved fuel economy unless we try it for ourselves.

Showing up in a simple can, Energy Release calls its product an anti-friction agent whose job it is to protect and condition metal surfaces during the cleaning process. After application, Energy Release says one should expect reduced friction of engine internals and increased performance.


  • Cheaper than the dirt in your car's engine


  • Relative lack of reviews

Bottom Line

  • Vast majority of reviews are full of praise


Which is the best engine flush?

Although everyone may have varied opinions about which engine flush is the best, every decision narrows down to two important factors, namely ‘best overall performance’ and ‘best value’. Some engine flushes that fit these criteria are listed below:

Best Overall

Liqui Moly 2037 Pro-Line ( Buy here!)

With around a 4.7-star rating from more than 4,400 users on Amazon at the time of this writing, this engine flush can be categorized under the ‘best overall’ product that is easy to use, and is compatible with catalytic converts as well.

Best Value

Sea Foam SF-16 Motor Treatment ( Buy here!)

This engine flush enjoys the title of ‘Best Seller’ on Amazon and has a 4.8-star rating from more than 16,700 users at the time of this writing. With these decorations, the product can be safely categorized under the segment of ‘Best Value’.

Do engine flushes actually work?

Yes, they do. When you buy a preowned car that has been driven somewhere over 100,000 Kms, and don’t know how frequently its engine oil was changed, some mechanics might suggest using an engine flush to ensure the safety of your vehicle.

The Process

To use an engine flush, the mechanics take out some amount of engine oil from your car and top up the space with a good quality flush. When you drive the vehicle for a couple of miles, the engine flush circulates properly and removes any unwanted gunk from the walls that might harm the system.

However, you must replace the engine oil as soon as you possibly can to prevent the flush from damaging the engine in the long run.

Will engine flush damage engine?

Yes, they can damage the engine if you don’t change the oil after mixing it with an engine flush and running the car for a couple of miles. The reason is, that engine flushes contain harsh chemicals that are supposed to remove gunk from the engine, if used for a long period, they may harm the system.

The truth is, no car manufacturer would recommend using an engine flush. Instead, they strongly suggest getting your car serviced and engine oil and filter replaced on time. With these driving habits, it is unlikely that your car would ever need an engine flush to clean the engine.

Why you shouldn’t use engine flush?

Although the idea of using an engine flush isn’t that bad, there are a couple of reasons why you should avoid going that road. Some of the major factors in this context include:

Not Required

If you are getting your car serviced and engine oil and filter replaced regularly and on time, the chances are that no gunk that may harm the engine would ever get deposited. However, it is imperative not to leave the vehicle unused for long.

Need of Oil Change

Once you use an engine flush, it becomes extremely necessary to get the engine oil changed after driving the vehicle for a couple of miles. This would prevent the engine of your car from getting harmed by the hard chemicals that the engine flush contains.

Not Recommended

As mentioned earlier, no car manufacturer recommends the use of engine flushes as they may harm the engine. They rather suggest getting your vehicle timely serviced and its filter and engine oil replaced from time to time. The vendors and the authorized service professionals also advise using high-quality engine oil for long-lasting performance.

From time to time, TTAC will highlight automotive products we think may be of interest to our community. Plus, posts like this help to keep the lights on around here. Learn more about how this works.

(Editor’s note: This post is meant to both help you be an informed shopper for automotive products but also to pay for our ‘90s sedan shopping habits operating expenses. Some of you don’t find these posts fun, but they help pay for Junkyard Finds, Rare Rides, Rental Reviews, and whatever else. Thanks for reading.)

[Main Photo Credit: Phanu D Pongvanit/ Product images provided by the manufacturer.]

Vivek Nayyar
Vivek Nayyar

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2 of 10 comments
  • Dukeisduke Dukeisduke on Aug 10, 2020

    Matthew, you must be a young whipper snapper, if you're not familiar with Wynn's products, and Marvel Mystery Oil. Since time immemorial (or so it seems), MMO (an "upper engine lubricant") has been the go-to for engines that have sat for long periods of time, where there's some question of whether they will crank or are seized. You typically pour or squirt a little in the cylinders (through the spark plug holes), and let them sit overnight before first turning them over by hand, then cranking. And Wynn's Products was a drag racing sponsor back in the '60s and '70s, including being the title sponsor for Don Garlits' "Wynns Charger" Top Fuel dragsters.

  • RHD RHD on Feb 21, 2022

    How to write a TTAC article for enjoyment and small monetary referral remittances: 1) Search Amazon for an automotive product 2) Sort by customer ratings 3) Assume those writing the ratings have a clue about what they are saying 4) Assemble them into an "article", complete with "Buy here!" links 5) Duck when you are told that there are very good products for sale in real stores that are as good as or better than the stuff on Amazon. 5) Be sure to omit such articles from your resume when applying for journalism work elsewhere.

  • SCE to AUX I've always said that consumer/business pressures will reign in government decrees, as they have in the past in places like California. That state has moved the goalposts many times for "ZEV" mandates.But the problem is the depth of politicization of the EPA. Mfrs need continuity and long-term commitment to requirements, not living on a 4-year political cycle of who's in the White House and Congress. Your President - whomever that is - isn't going to be around forever.
  • Dukeisduke The administration is slowly dribbling out details of the change - it's like they don't want to piss off environmentalists, the auto manufacturers, or the UAW. John McElroy covered this very well in today's installment of Autoline Daily: AD #3751 - 2024 U.S. EV Sales Could Grow 43%; China Price War Spreads To ICE; U.S Vehicles Biggest Ever, Also Lowest CO2 - AutolineAlso, even though vehicles in the US have gotten larger, heavier, and more powerful (thanks to the shift away from sedans to trucks and SUVs), according to a year-end report by the EPA, in 2023, average fuel economy was at its highest ever, and CO2 emissions of new vehicles were at their lowest ever ( The 2023 EPA Automotive Trends Report: Greenhouse Gas Emissions, Fuel Economy, and Technology since 1975, Executive Summary (EPA-420-S-23-002, December 2023 ).
  • Golden2husky How about real names instead of alphabet/numeric soup?
  • Alan I think its the far left that want to ban fossil fuel powered vehicles. The left can mean many things. So don't place all into the "Left" if they don't believe in your right wing agenda.If one looks at a breakdown of political beliefs you'll find approximately 20% are dedicated wackos on the right, sort of Trumpian types. The same occurs on the left 20% are wackos, I call them Green types.This leaves the middle 60% shaking their heads at the nonsense, BS, misinformation, lies, etc that is spruiked by the extremes of both sides of politics.Australia is lucky in some respects as we have multiple political parties. The Labour Party (Dem equiv) don't have the extreme left as they migrate to the Greens. The Liberal Party (GOP equiv) don't have such luxury and has been infiltrated by right wing knobs.So, you'll find many Dems might have more conservative views than those that are GOP and vice versa.Stop with this nonsense.I don't envisage a ban on fossil fuel powered vehicles in Connecticut as this will not fit in with the economic development of the State. There will be changes of course.This is nothing but a piece of red meat.