Thursday, December 13, 2007

Bonehead Award: Engine Oil Flush Machines

The fifth annual bonehead award goes to the makers of engine oil flush machines, as well as those businesses who are telling their customers that engine oil flushing is a necessary part of engine maintenance. At best, engine oil flushing does nothing but lighten the consumers wallet. At worst, it thins out the oil causing accelerated engine wear. And at the very worst, it causes chunks of sludge buildup to become dislodged and to clog up the oil filter-which would result in catastrophic engine failure!

The Scenario
It’s time for you to change the oil on your one-year-old Jeep Cherokee. Your local repair shop is closed for vacation and the dealer is too busy to give you an appointment right away. Rather than wait, you decide to go to one of those fast-oil-changes for their 10-minute $19.95 oil change special. No harm done, just so long as you change the oil according to the maintenance schedule--just as you’ve done for the past 20,000 miles.
A few minutes after they begin, the oil change guy comes out with a stern look on his face and his latex-covered hand held out. He holds something in it for you to see-some of your motor oil! He says, Look at this filthy motor oil. It is way to dirty, and now your engine is full of sludge. Your engine must be cleaned or this will cause it to blow a gasket. You can’t believe your eyes, as the oil looks pretty dirty. But you’ve always followed the recommended oil change intervals. "Why is this happening to your engine?" you ask. The attendant tells you that changing your oil is not enough, that you need to have your engine flushed every year or every 12,000 miles. He hands you a pamphlet that has a title with large bold print:

"Just changing your oil is not enough"

He walks with you out to your car, which is sitting astride a lube pit. In the pit is another lube tech who stands next to your car's rear differential. He is looking up at you with a grim look on his face, and he's holding up his hand for you to see a blob of dirty oil. The first attendant picks up your air filter to show to you, and then points to the hand of the other attendant under the car. He says the air filter is much too dirty, pointing to it. Then he points to the other man’s hand and says that the dirty oil came from your fourwheel-drive unit, explaining that it is very dirty and must be changed--or the four-wheel-drive unit will go bad. More grim looks. The truth or a scam? Can this man judge the condition of your motor oil and gear lube by sight? Does the fact that the oil has darkened, mean that it is 'too dirty'? Could a slightly dirty air filter also be bad? Even more importantly, what happened to that $19.95 oil change special? You're now looking at about $200--which is mostly the cost of the engine oil flush, which is $99.95.

Sensing that there is a big scam going on, the Good Morning America news team decided to do an undercover sting operation. They wired a reporter with a camera in the top button of his shirt, and sent him to several local and national fast-oil-chain places in New York. They found the tactics varied little from place to place. The oil change attendant would show the reporter the dirty oil, and then follow with a stern brow beating for not changing it frequently. Then, as if a miracle panacea had suddenly appeared, they said they needed to do this special engine flush in order to save it from the wrath of engine sludge. Just like the pamphlet says, this little R2 universal flushing unit will clean the engine, remove varnish, sludge, and all the engine wear particles, leaving the motor with more horsepower, and lower tailpipe emissions. And the scenario is repeated all across America, not only in the fast-lube chains but in car dealerships as well. This new scourge, the oil change machine, has added a generously new profit source for shops that own one. for the most part. You just need more frequent oil changes that's all. And if you do have sludge, the flushing machine won't even touch the sludge buildup! Oh, that's not all. The oil flushing service is not approved by the automakers, and will void your warranty. And even worse, this service is likely to do more than just lighten your wallet by $100 or so it is likely to cause accelerated engine bearing and cylinder
wall wear!

The Problem
Here’s how what we call the 'R2D2' flushing machines work. After the engine oil is drained and oil filter removed, two hoses from the R2D2 unit are attached to the motor, once where the oil filter goes, and the second to the oil pan drain. Then R2D2 pumps a warm solvent into the engine and then sucks it back out. Then the machine pumps it back in again. R2D2 circulates solvent for maybe 10 to 15 minutes. Then the final 'sucker' cycle is run, and R2D2 is now finished doing his deed of fighting the evil sludge. While this may look beneficial and harmless, there are several lurking
'dark forces' with these 'R2D2' machines:

The biggest fiction is that it never addressed sludge in the first place it never even touches it! Engine oil sludge forms on the inside of the engine, mainly inside the valve covers and the oil pan. These areas are completely removed from the flushing solvent oil that R2D2 pumps through his hoses. The solvent runs through the oil-drilled passages, and never touches the sludge. The analogy is having a dentist wash the patient's hair in order to remove the dental plaque buildup that is on his teeth! The shampoo never touches the plaque and even if it did'it wouldn't dissolve
it in the first place.

Even if the R2D2 unit did somehow loosen the sludge, there's a big danger of the sludge breaking loose and clogging the pump. If this were to happen, the engine would lose oil pressure and quickly self-destruct!

Chunks of sludge would work loose, and then be drawn up to the oil pump intake where they would get suckedup against the intake screen plugging it up. No oil pressure, dead engine.

R2D2 leaves about ½ quart of hydrocarbon solvent behind in the engine.
This hurts the engine in several ways:

1. It dilutes the oil. Solvents are actually lightweight mineral oil (hydrocarbon) oils. Don't fall for the ruse that 3-weight mineral oil isn't a solvent. It is a solvent, and it dilutes your motor oil by breaking down the viscosity improvers in the additive package. The resulting loss of viscosity causes the oil to be less viscous. Adding ½ quart of solvent to a typical fill of 5w-30 motor oil will turn it into 0w-20 weight oil. This thin oil won't provide adequate engine protection, resulting in increased camshaft and bearing wear especially during cold startups. NOTE: Applying vacuum to the engine oil pan won't remove the solvent hung up inside the engine. At least ½ a quart solvent will remain in the oil passage drillings, bearing saddles, on ledges and flat surfaces inside the engine, as well as in the pockets and recesses in the block and head.

2. Exposure of solvent to engine seals and O-rings may harm them resulting in accelerated seal wear and subsequent lack of proper function.

3. The remaining solvent evaporates after the engine is operated for an hour or two. One the oil reaches operating temperature, the lightweight oils will boil out and vaporize, being drawn away by the crankcase ventilation system (PCV). This leaves the engine ½ quart low on oil. People who just had their oil changed aren't likely to check the oil level right after a change, and will wind up operating the engine low on oil. This will accelerate oil break down and oil contamination, resulting in compromised engine lubrication. By the time the owner checks it, it could have fallen
below the add level.

Double Speak

Like all snakeoil salesmen, the story gets changed in order to keep you believing in their product. Bilstein, a major player in the manufacture and distribution of R2D2 flushing (only they call it the R-2000) makes several questionable statements. Here's a litany of some of the claims and statements that we've collected:

  • Originally, Bilstein recommended engine flushing be done once a year, or every 15,000 miles. Since the TV investigative report, they backed off, saying the R2D2 should only be used “as needed”. The “annual” and “12,000 mile interval” recommendations have been quietly dropped. We wonder why?

  • "[Engine oil flushing] is the only way to change the oil completely in some engines." And 'Just changing the oil isn’t enough.” Why isn't consecutive draining and refilling of the oil enough. It always has been. Why wouldn't the detergent-dispersant additive package found in motor oil do the same thing? We believe it does, and does it without harming the engine nor your wallet.

  • "When [engine] particulate levels are, internal engine friction is reduced, fuel economy is improved and tailpipe emissions drop." This leap of faith is totally without merit. The presence of engine particulates may cause accelerated engine piston ring and bearing wear, but have no direct effect on engine power (internal friction), fuel economy, or tailpipe emissions.

  • “Engine flushing is effective in reducing 10 key engine oil wear elements and oil contaminations between 33% - 100% - over and above a standard oil change." More on this claim below.

  • The Bilstein technical authority says (in a letter of August 15, 2001) that the Bilstein engine flush brings a motor back to something he calls the "new vehicle oil quality standard". However, there's no such standard known by the industry. But this letter implies that if there's some kind of standard to which all new cars must adhere.

  • The Bilstein website (which keeps changing its recommendations) now touts that hooking up an R2D2 to your engine will result in... “Improved oil cleanliness also enables vehicle owners to extend their oil-drain intervals by up to one-third. The real pay off from removing engine contamination is the enormous reduction in wear rate and the time between engine overhauls.”

Test Procedures, Controls, & Blinds

"To conduct the study, Bilstein contracted with three independent, certified testing laboratories to measure the effectiveness of [Bilstein] oil flush products in reducing vehicle emissions and improving performance." The three independent testing labs were not used to produce three independent courses of data analysis, as you would be lead to believe. One lab tested the motor oil, another tested emissions, and another tested horsepower. There certainly was nothing independent about their involvement. Funny, there's no such thing as a "certified" testing lab. In this country, if you want stalwart engine data tests to be run, there are two well-known labs that just about everyone uses, Southwest Laboratories and EG & G Testing. They are both located in San Antonio, Texas. Neither was used.

All the data shown was gathered without a control group. The subsequent claims are false and misleading claim because they are based on questionable data. Most importantly, no control group was used in their studies. A control group would be needed to establish a "standard oil change" baseline in order to make comparisons. Otherwise, all comparisons are made with the engine being treated, and the treatment effect is confounded by the treatment itself. Here's some specifics:

1. Tailpipe emissions normally drop after an oil change. Dirty oil is the most likely cause of failed exhaust emissions, and simply changing the oil is all that’s necessary. And since lighter oils are less viscous, they exhibit less engine drag. The thinner nature of the oil allows the engine to turn over more freely, thereby increasing less fuel requirement and lower emissions. Ditto for horsepower. A control group data would clearly show this fact.

2. The same (or better) results would be had if the engines were simply given two oil changes instead of an oil change and engine flush. If the engine was dirty inside, a second oil change would do the exact same thing as the engine flush. In fact, consecutive oil changes may induce even less wear metals because the oil flushing machine is allowing the oil to thin out and thereby inducing some wear metals from the subsequent metal-to-metal contact of the bearing surfaces
caused by the thinner oil. The data was gathered without a double-blind. The operator could have easily affected the outcome.How long did the engine run before
the emission and horsepower tests were conducted? A cold engine will show poorer results. Was the engine fully warmed after the flush? Was engine operating temperature manipulated for gains in horsepower and emission control?

Choice of an improper test procedures could affect the outcome.
What emission test was used?
1. The Federal Test Protocols (FTP) 'idle sampling only' test would typically show improvement with a lighter weight (lower viscosity) motor oil. Therefore, comparisons between an engine operated with different weight oils are totally spurious.
2. The emissions test scores touted in the sales literature show decreases in hydrocarbons (HC), Carbon Monoxide (CO), Nitrates of Oxygen (NOx), as well as Carbon Dioxide( CO2). Some other variable must have been manipulated as these scores aren't possible. Not from just changing the oil. For one thing, a cooler engine will
have lower NOx scores that a hot one. Opening the door (or a fan) would let more cold air into the engine. This lowering of the combustion temperature would also lower NOx. Another way is to manipulate the exhaust catalytic converter. Simply precondition the engine and allow it to warm up enough to light off and begin working. That's a very simple way to lower NOx.
3. The emission tests also showed a drop in CO2 emissions. This is proof that the engines weren't fully warmed when being tested. The CO2 emissions are supposed to go up rather than down! When the HC and CO emissions decrease, CO2 increases! Decrease in CO2 emissions is a bad thing, because it is accompanied by increased HC and
CO emissions the bad guys. This bad science has an unbalanced chemical equation. The idea is to lower harmful gasses (HC and CO) and increase CO2 and H2O (water vapor) in the exhaust! Reporting a decrease in CO2 points to faulty sampling methods (or bogus numbers).

The oil analysis test procedures could easily be rigged to show a decrease
in engine wear metals.
1. One test touts that the R2D2 machine lowered levels of MO (molybdenum) along with the other engine wear metals--as if it were a wear metal! In fact, MO is an important oil additive used to control metal scuffing. The data itself is proof of faulty test procedures. A reduction of MO is clearly NOT beneficial, and throws suspicion on all of the results.
2. Other test data show a 10% reduction of NO3 -which indicates oil nitration. This item has nothing whatsoever to do engine wear metals, sludge, or even engine flushing. Oil nitration is caused by the breakdown of the oil by abnormal engine operating conditions, such as extreme temps, lack of lubrication, or mechanical malfunctions (stuck thermostats or spark timing problems). Flushing the engine has nothing to do with reducing NO3. The data again throws suspicion about the engine being tested, which appears to be operating under abnormal conditions.

Post Hoc Ergo Hoc

The bad science behind oil flushing machines serves as an example of the "post hoc, ergo hoc" fallacy (because of this therefore that; i.e. do this, get that). The fallacy would lead you to believe that if you do this (have your engine oil flushed), you will enjoy these results (better emissions, better gas mileage, more power). However, the background facts involved in the testing session aren’t ever taken into consideration. In a classical example of the post hoc fallacy, you would say, "Heroin addiction is directly a cause from drinking milk." It's easy to reach this conclusion if you interviewed 100 heroin addicts, asking if they drank milk.
Close to 100% would say, "Yes" leading to the conclusion that drinking milk leads to heroin use. But what if you interviewed 100 non-addicts and asked them the same question? Clearly the use of a control group in this study would have showed that the results attributable to some other factor, and were not the effect of the engine flush. Supporting paperwork provided by Bilstein show a number of new car dealers selling this service, for as high as $129.95 (plus tax and hazardous waste fees). While, to some, this shows credibility to oil flushing, it is against the manufacturer’s recommendations. When questioned by the ABC reporter, all of the Big Three car makers recommended against using engine oil flush machines. If the engine were to suffer from a lubrication failure and the manufacturer found out an engine flush was used, the warranty would be voided.
Finally, a test report conducted for Ashland (Valvoline) found its way into the hands of the ABC reporter. The test report, dated March 5, 2002, says that the test... Has not been conducted in a valid manner in accordance with Test Method D5302 (sequence VE). When asked about the invalid test results, the Bilstein spokesperson said 'You weren't supposed to see that test. Engine oil flushes do have a small place in the automotive repair industry. They could be used to flush the oil when there's contamination by coolant, water, sugar, or brake fluid. Otherwise, engine oil flushing is not needed. We believe that the this service is actually a disservice to the consumer and constitutes a major rip-off.


  1. Good stuff. I try to even stick with the same type of oil from onr change to another -- I'm certainly never going to put solvent in there! Bad idea.

  2. Good article, thanks for sharing it. I've always believed that oil flushing is a ripoff and now it's confirmed.

  3. Ok so should I just skip the oil flush and just do the oil change (dino to syn)?
    Would that be acceptable?

  4. The Express Lube where I got my oil changed last week recommended an "Engine Flush". I declined and told them I would wait until next time. After searching online, I will definitely tell them "NO" in no uncertain terms next visit. I have an older car and cannot afford a new engine.

  5. do not listen to this article whoever wrote this hasn't researched different flushes and the way they are made. I have worked on cars for 12 yrs as a hobby and you want to stay away from solvent based flushes only use mineral based flushes such as gumout

  6. Gotta question. Have taken apart the oil pan from the block. Replaced oil pickup and screen. Decided to run marvel mystery oil mixture through motor, resulting in dislodged sludge and reclog of screen. What have I got to lose with an engine flush to reverse the clog of the screen and vacuum out residue in oil pan? The alternative is to pull the pan again, clean or replace the screen, and wait for the next clog. 132 k on motor.

  7. The author of this article gets the "BONEHEAD AWARD" before spouting his great knowledge learn the subject.An EDE flush machine cleans with engine running every part is oil wetted, the filter can't clog as the machine filters in a dialysis loop. Then a rinse cycle neutralises the active non solent cleaner.Leaving a clean engine for new oil

  8. So how do you find an EDE Engine Flush service in Houston, Texas?

  9. Greetings from Las Vegas! I'm having the Mercedes dealership flush my 1997 S500 this week. Seems I may have driven the car 20k miles without a documented oil change. I'm really not sure. -shoulder shrug- I switched over to Mobil One synthetic years ago. The car has 86k miles, so if they suggested it, I trust their recommendation after 11 years of great customer service. Will report back if/when my engine blows up, leaks a drop, or is low a half a quart within the week/month.

  10. I have regularly used 10 minute flush, at every oil change, in my Dodge pickup since I bought it new. It seems like a good idea to me as Chrysler seems to have a problem with engine sludge.

  11. Shawn from Las Vegas, so what happened with your engine?

    The Lube Shop I took my Suburban too recommended an enigne flush. THe truck had been sitting for 6 months and had only been driven 1,100 miles in 13 months. I took it in just for an oil change and the oiul come out thicker than a milk shake. Should I do the engien flush?

  12. I had an engine day my engine blew.....4k problem....

  13. Any comments to Motorweek (Pat Goss Garage) show of flushing?

  14. I had an oil flush and it killed my whole family, and caused a black hole to open east of the Tanza Nebular... Don't do it unless you want a complete disaster in karma...

  15. You really should research your subjects a little closer, or take this useless bit of info off the web.
    To the article writer. First of all it is 3 years old and many things have changed in Engine Oil Flushing. Secondly, we have NO solvents in our solution. Secondly the US Government as well as the US Military says our services work. I await your call at anytime at 904-230-5414 to discuss further.
    Lou Abbruzze, President owner, LSA Int'l.
    But I am sure your call will never come.

  16. This article has some fair points, but engine flush that you add to the oil and run the engine before the oil change, DOES remove sludge and the viscosity of oil is not affected. As for needing heavy weight oil in colder weather, the truth is quite the opposite. Lighter oil flows better in cold weather, heavy oil thickens at cold temperatures and is not pumped fully around the engine for the first few vital moments.

  17. i use a engine flush once a year , :sea foam: the product has been in service since 1942 and is fully guarranteed , also the same product can be used in the gas tank to clean out the fuel lines and jets , this is the only product i use , as it works and you can feel the difference in preformance in your vehicle .
    i always read up on a product before i ever use it

  18. guys, your motors WILL reach over 250,000 miles just with regular 3,000 interval oil change don't let them steal your $$$, It's always being like that.

  19. Whoever wrote this article is the bonehead and shows this by contradicting himself over and over again. Here's an example.."The resulting loss of viscosity causes the oil to be less viscous. Adding ½ quart of solvent to a typical fill of 5w-30 motor oil will turn it into 0w-20 weight oil. This thin oil won't provide adequate engine protection, resulting in increased camshaft and bearing wear especially during cold startups. AND THEN...

    And since lighter oils are less viscous, they exhibit less engine drag. The thinner nature of the oil allows the engine to turn over more freely, thereby increasing less fuel requirement and lower emissions.

    Make your mind up, how do you expect to impart knowledge if you keep contradicting yourself. Ask any SAAB 93 driver if they have a problem with sludge and if regular oil changes are enough to solve the problem, I know from personal experience over 20 years of driving.

  20. Hello People, I Went to a Castrol Lube Express a few weeks ago for an oil change, and Ta-Da! I was told I needed an engine flush on my '07 Chevy Uplander which I've owned for about a year now. Yes, I've given it an oil change every 3000 miles and didn't know about the controversy surrounding this issue. So yes, being concerned, I paid for the flush and a power steering flush as well. I can honestly say that I did feel a difference in performance afterwards in as well as a difference in steering. (the power steering seemed to be sticking a bit before). Now I cannot say whether or not this engine flush works, but I hope so as I did spend about $180 on this service. If it is in fact a scam, I can only hope that something will be done to outlaw such practices as not everyone is knowledgable about such things. Even when we try to be informed, we find different views on such issues which can further serve to confuse.

  21. we did this and the next day the engine blew :(
    I say no to engine flush!

  22. Let's hear it for Seafoam! Great sons 2001 Audi A4 Quattro 1.8T(notorious for engine sludge) went low on oil. The low engine oil light came on. He changed the oil(always synthetic) and the sensor never cleared. I suggested he add Seafoam to the 3 day old oil change. It took 2 days but the sensor finally cleared. Never let your oil turn black. Change when a light brown in color.

  23. I am 70 years old and have been playing with automobiles for approximately 56 years after building my first hot rod at age fourteen. I have enjoyed playing with old luxury classics so you would think that people with money have the money to change their oil as it should be changed. Records indicate they do. This last car that I am finishing up is a "98 Jaguar XJ8 Vanden Plas. The maintenance records for this car indicate oil changes every 2,500 to 3,000 miles. The mileage is just barely over 100k. I partially tore the engine down to replace the known parts that go bad before they go bad such as the timing chains and tentioners, etc.. This engine has only been ran with a full synthetic oil. There are signs of sludge building up below the valve covers. There were also indications of sludge starting on the inside of the timing chain cover. Jaguar also has small metal screens within the engine that are only reachable by tearing the engine down. This engine acts as if one of the screens are partially clogged. I've used a Blistein r-2000 for over ten years. I used to drag race until 1974 so I'm used to tearing an engine down frequently. The engine flushing machine I have used does an excellent job of cleaning up the inside of an engine. The proper way is to drain the oil, run the flush for twenty minutes or more if you are working on something else. Drop the pan and clean it out, change the filter and do it for the second time. Anyone with any knowledge of engines know that when you build a new engine, you crank it for two minutes without the main distributor wire in order to lube the engine prior to starting. The flush machines cleans the engine thoroughly if used as I stated. Simply start the engine as you would when building a new one. The author of this article meant well but if you read carefully you will get the impression he has no practical knowledge of automotive engines. He is right that many places rip people off but that does not negate the use of mechanically flushing an engine out. I've never experienced an engine oil that would keep an engine clean unless one changes the oil every 500 to 1000 miles. I would also venture to state that sludge buildup begins as early as 30k. It is the break down of the additives with the oil that create the sludge. City driving is murder on engine oil. I recommend flushing your engine at least every 20k but only with a mechanic that you trust. It needs to be done right in order to do what it is suppose to do for your engine. These oil additives are a joke. The 99% working ingredient in these products is nothing but kerosene called another name. If you read the author's article carefully, I would venture to say that the author is upset probably with Bilstein.

  24. FYI,

    288,000 mi on my 3.8 L Ford Vulcan engine. No oil passage flushing to date, just regular (i.e. 3,000 - 6.000 mi) oil changes. Although not mentioned by the article, I'd be most concerned that the bearings will have been cleaned of oil by the flushing solution. Finally, I once lost a camshaft due to oil sludge buildup (failed to change the oil properly). When repairing it, I found the sludge was fairly impervious stuff to the solvents I applied. I doubt until verified that a mineral oil would be able to remove it.


  25. Four weeks after engine flush my engine blew. I had no problems with my engine before this. Do not do it.

  26. I work with people that offer these flushing machines and services. Yes they try to oversell it, just like ANY other industry in this planet. But engine oil flushing is only necessary when there is too much sludge in the engine. If you follow your service intervals you never have to flush your engine. And BTW, IF your vehicle's manufacturer requires an oil flush, you must do it for the warranty to stay in effect. Otherwise, you'll only save a few bucks to lose a few thousand if and when your vehicle fails due to some manufacturing issue.

    Vehicles are a waste of money, everyone knows that. So suck it up.

  27. WHY would FORD tell me I need an engine flush on my Mustang at 15,000 miles? I'm not a kid and I don't drive her rough. Granted I don't put a lot of miles on her, BUT I do take her on the freeway every now and again.
    Did I get ripped off?