Top 7 Urban Legends About Motor Oil

Top 7 Urban Legends About Motor Oil

What's True and False About How We Use Oil in Our Cars?


Even though Edmunds has definitively debunked the myth of the 3,000-mile oil change, we keep hearing wildly contradictory information about engine oil, what type to use and how often to change it. So we issued a call for oil myths, legends and lies, and gathered up a list of the top puzzlers. We then put these questions to the experts and came up with some interesting answers. Here's a list of seven oil myths and realities to guide you through this murky subject.

1. Change your oil every 3,000 miles or three months — whichever comes first. We've said it before and we'll say it again: This is a myth for the vast majority of modern cars. The 3,000-mile oil change is the credo of the quick-oil change industry and dealership service departments, designed to regularly get you into the service bay. (Jiffy Lube recently abandoned its advocacy of the 3,000-mile rule, but clings to severe-schedule advice with which Edmunds disagrees. More on this later.)

Experts agree that the oil in today's cars should be changed at the designated intervals in the owner's manual or when the car's oil life monitor light appears. (The average interval for 2010 cars is around 7,800 miles.) Oil experts and car manufacturers say that oil chemistry and engine technology have evolved tremendously in recent years, extending oil change intervals.

"If customers always just stayed with the 3,000-mile recommendation, there'd be these great strides in the robustness of oil that oil companies have made [that] wouldn't be utilized," said Matt Snider, project engineer in GM's Fuels and Lubricants Group. Consumers, he said, would be "throwing away good oil" if they hewed to the outdated 3,000-mile rule.

2. Change your oil before a long road trip. There is some truth to this. It's definitely a good idea to look your car over before long drives, says Dan Edmunds, director of vehicle testing for However, if the oil change interval is not scheduled to occur during the trip, it is not necessary to change it preemptively. If the oil change interval would arrive during the trip, then it's a good idea to change it before you leave.

But Edmunds cautions that having service work performed just before a trip carries a risk. He was once driving miles from anywhere when a car passed him, trailing oil. It turned out the owner had just had her car's oil changed, and the shop had not properly tightened the drain plug. It had vibrated out. Edmunds suggests scheduling a service visit for about a week before leaving on a big trip, just to make sure everything is working properly before you hit the road. Here's more information about when to change your oil.

3. Nearly all cars should be serviced under the "severe" maintenance schedule. This oft-cited rule is a myth the quick oil-change industry (including Jiffy Lube) uses to bolster more-frequent-than-necessary oil changes, experts tell When manufacturers say "severe," they mean situations in which vehicles pull heavy trailers, or cars race on closed tracks. It also applies to taxis or emergency-response vehicles that can idle for hours at a time. Just plain old stop-and-go traffic doesn't automatically bump people into the severe schedule. For further proof, consider this: A number of automakers, including Ford and GM, contacted Edmunds data editors to request that the maintenance section of Edmunds' site substitute the normal maintenance schedule for the severe schedule that had been displayed. If your car has an oil life monitoring system the severe-versus-normal question is moot.

4. Check the oil on the dipstick. If it's black, change the oil. Experts say this is a myth, as is the related notion that you can identify spent oil by smell. "That is old school," says Kristen Huff, vice president of Blackstone Laboratories in Fort Wayne, Indiana. "Oil is meant to get dark — it means it's doing its job," she says. As GM's Matt Snider says in this video, different additives change the oil's color. The bottom line: Black oil still has plenty of life left in it.

5. When you buy a new car, change your oil at 3,000 miles to remove metal particles from the engine break-in process. There might be a grain of truth to this, according to the experts at Blackstone. Oil samples from engines during the first 3,000 miles of driving show elevated "wear-in" metal levels, coming from the pistons and camshafts, says Ryan Stark, Blackstone's president. But he added, "To me, it doesn't make that much difference because if the filings are big enough to cause damage, they will be taken out by the oil filter."

However, a Honda spokesman says its cars come from the factory with a special oil formulation for the break-in period. Honda advises owners to not change the oil early. Stark said Blackstone Laboratories' test of Honda's break-in oil shows it contains molybdenum-disulfide, an anti-wear additive. But Stark said Honda is the only manufacturer he knows that's using special break-in oil. The take-away? If there are any special break-in recommendations from the manufacturer, follow them. And consider analyzing the oil at 3,000 miles.

6. Once you use synthetic oil, you always have to use it. This is a straight-up myth. In fact, the line between synthetic oil and petroleum-based oil is blurring because the two types of oil are often blended, says Edmunds Engineering Editor Jason Kavanagh. "As long as the oil meets the service and viscosity requirements set out in your owner's manual, you can switch back and forth as much as you want," he says. For more information, watch this short video.

7. Synthetic oil is better for your car's engine and it improves your fuel economy. Myth. Steve Mazor, manager of the American Automobile Association's Research Center, says his testing shows that synthetic oil is generally a superior lubricant, but adds, "I'm not sure it is worth the extra cost — you need to take some of the [manufacturer's] claims with a grain of salt."

Blackstone's Stark says he has not seen data to support claims that synthetic oils boost increased fuel economy. "There is a school of thought that says the synthetic oils are slipperier and allow the engine to spin easier — I don't know that I believe that." Watch this short video for more on the ongoing debate over synthetic and conventional oil.

To find a dealership that knows how to treat shoppers right, please visit's Dealer Ratings and Reviews.



  • I worked 20 years at the biggest trucking co. in the us as a diesel mechanic , and we had to change transmissions and differentials on a frightening high rate until we started using synthetic gear lube, after that we nearly had to close the rebuild shop because we didnt have the business. Also we started using synthetic blend motor oil and doubled the oil change interval to 25000 miles, that's not a typo, we also went from 350,000 trade in intervals to over 1,000,000 trade in interval ask Yellow freight i have been retired since 95 so some things could have changed but I'm telling it like it was

  • 16tons 16tons Posts:

    I worked for many years in the Marine industry as a Marine Engineer and as Project Manager for Ship Repair and new installations. I have also written dissertation on the 'oil change interval' myth. We change our engine oil far too often. The only true way to determine oil change frequency is to send it out for oil analysis. One vessel I served on, only had it's engine oil changed once per year (and only because they thought it was the right thing to do) even though the oil analysis came back certifying the oil as fine. These engines were only turned off once every month or two, for a long weekend to provision the ship.

  • Why did you not advise the readers that in order for the maintence reminder system to work correctly they must use oil that meets the very specific requirements of their vehicle manufacturer? Articles like the one above that do not spell all of details out clearly for the consumer are careless and misleading. Some of the reminder systems can allow for a maximum of 18,750 miles (Mercedes-Benz) between services (typical use normally has the system expire around 11K-12K). Failure to use the manufacturers approved oil will result in an engine failure with that system. Which also brings up another issue, in the event that a reminder system is accidently reset even if the correct oil was used, some manufactures specify that servicing should be done at 3000 miles (GM, check your owners manual!).

  • Please coordinate your advice to the readers with this article from the New York Times about engine sludge formation. Back when this article made news none of us really knew what was happening and we saw the manufacturers take it on the chin. Today through continuing edication we now know what was really to blame, and it was the oils we were using. It wasn't extended drains, although in some cases that easily may have played a role. It wasn't the engine design changes which were made to reduce emissions, although they did contribute to the issue. Again the fault was with the API and ILSAC oil specifications at that time. In order to educate the readers as you have tried to do here, you must report all of the facts, and not just cherry pick them to your convenience.

  • philip17 philip17 Posts:

    Using the correct oil for your car is essential. In my story I quote an Edmunds Engineering Editor as saying, "As long as the oil meets the service and viscosity requirements set out in your owner's manual, you can switch back and forth (between normal and synthetic oil) as much as you want." Oil requirements are listed in your car's owner's manual along with how often the oil needs to be changed. If your car has a maintenance minder, which lets you know when the oil needs to be changed based on a number of factors, take the time to understand what it is telling you. It will save you money and still ensure your car runs reliably. Thecardoc3 has included a link to a New York Times story on sludge. This is a problem that is avoided by maintaining a car correctly. How widespread is the sludge problem? The article says: "Given the millions of engines in the United States, the number of sludge-related failures is microscopic, said Robert J. Last, vice president of operations at FEV Engine Technology, a consulting firm in Auburn Hills, Mich." Philip Reed, Senior Consumer Advice Editor,

  • ""As long as the oil meets the service and viscosity requirements set out in your owner's manual," Hi Mr Reed. If it was only that easy today. We often run into issues where consumers don't comprehend exactly what "the service" portion of that statement really means. For example a new GM automobile that requires 5W30 actually requires an oil with the dexos1 label to be absolutely certain that it meets GM specifications. You can see more about that here. It's really getting to be a problem when it comes to proprietary specifications. Oils that meet a Ford (M2C929A M2C930A) or GM specification are actually thinner than the standard 5W30, or 5W20 that meets the API and ILSAC standards for those viscosities. European vehicles that require 5W30 actually require a thicker oil than what meets the API and ILSAC ratings. (See VW 502/504 and 507 specs, BMW LL-01 Mercedes 229.5 etc.) There is an eight hour class that I would recommend shops and technicians attend in order to learn why the technology that is in today's cars has caused this drastic change. Again failing to explicitly spell all of this out has the potential to confuse the consumer and lead them to make a mistake when servicing, or having their car serviced.

  • jmonroe jmonroe Posts:

    Here is my problem. I have an ’05 Hyundai XG 350 (3.5 liter engine) and I have religiously changed oil in it, to the tune of 15 oil changes and it will be 7 years old in April 2012. I’d say that is a lot, way more than what is needed. When I say “I have”, I mean me personally. I always used Pennzoil 10W30 with no problems at all. The car has a little over 43K miles and the engine thru a rod last week while my wife was driving it at about 35 to 40 MPH on a level road. By a very strange coincidence the dealer did the last oil change about a month ago and the windshield sticker says they used Pennzoil 5W20. Hyundai is not honoring their 10 year 100,000 mile warranty because somehow they showed higher mileage when they did service work in March of 2010 and my oil log for the next oil change by me in April 2010, showed less. I’m convinced that their mileage entry was incorrect but I could never prove that because I never noticed the mileage on the service slip I was given at the time of service. Because of this ‘typo’, by someone, they have denied warranty work even though the dealership admits that the engine is “very clean”. I’m in the process of appealing that now. Even though I noticed after the dealer did the oil change that the windshield sticker showed the wrong oil (5W20 when it should have been 10W30) I didn’t think it would be a problem at the time. However, now that the engine blew 500 miles later I’m beginning to wonder if this is just a coincidence or did the 5W20 oil cause the problem. Since they are pointing their finger at me, I’d like to point back at them if they are wrong. Can anybody out there comment about this? Thanks,

  • pacochess72 pacochess72 Posts:

    What oil does your owners manual say to use? Does it say to use a 10w30 or a 5w20? Also, If you can, try and get a sample of oil from your car and send it in to an oil analysis company to see what is what with your oil. You did not drive your car all that much to have a rod go like it did. Also, I did check to see what oil you should use in your car and 10w30 was the right type of oil to use. If they used a 5w20 THEY were in the wrong. Remember, a lot of Hyundai's cars now use 5w20. I think that whoever changed the oil didn't know about the 10w30 oil that was needed for your car or they ran out and they figured oh, it won't make any difference!! Good luck with your claim!

  • 5W20 is in fact the correct oil for your car. Hyundai does allow for 5W30, and 10W30 as alternates accordig to Mitchell On Demand. Hyundai has up till now typically accepted API and ILSAC standards. Do you have any other repair orders from any other facility that would show mileage on your vehicle during the time in question? How large of a discrepancy are we talking about?

  • bobbymcfly bobbymcfly Posts:

    So, the 'Service Representative' at a VW dealership actually claimed that my first oil change for a new 2012VW Golf should be at 10k miles. Hmm... Actually, the first place to look for oil change information should be your owner's manual. For example, in the 2012 VW Golf manual it is stated that a new engine can burn as much as 1 qt of oil per 1.5k miles. Assuming worst case, if you had waited for the 7.5k mile mark or later to change or check the oil, you would have already either been knocking, or would have generated sludge. ~$70 for an oil change compared with the cost of the car ( $20k-30k) is insignificant. An important factor is driving distance and style. 10k miles spent by driving 20 minutes each day in city traffic are completely different than 10k miles spent on long 50 minute commutes at 65mph on a highway (or faster). If you actually use your car, why not take care of it with a 3k - 5k mile oil change? Even if you do "waste good oil", I'm absolutely certain that a car engine is many-fold more valuable than all the "good oil" you waste. This is all terribly frightening, because the average driver does not question the dealership's advice, and read the full manual before hopping in their car. They then drive it until it's time to take it in for the 10k service. Ten 10k services later, and you're left with an engine full of sludge and no warranty. Time to buy a new car and repeat.

  • The dark motor oil may have to do more with incomplete combustion of gasoline as well as addition of ethanol than the ingredients/additives in the motor oil. Cars with higher mileage will have a build of sludge regardless of the detergents in the motor oil. Perhaps oil changes of 3,000 miles with the newer hi detergents motor oils may be prudent, but I would start changing the motor oil after every 5,000 miles with cars over 100,000 to prevent the build up of sludge.

  • shepperd shepperd Posts:

    Hogwash! Absolute environmental huxterism!The tree huggers believe that extended drain intervals are better for ''mother earth''.What about the environmental impact (not to mention the impact on your wallet) when you have to replace your engine with a new one?I bought a 2000 Chevy S10 with 74k miles and a cracked block.(I replaced the the engine)All due to the former owners changing oil every 10k miles and NEVER changing the coolant!(they were told the coolant was good for 100k miles)You can't change your oil (or other vehicle fluids) too often.By the way, buy oil and filters when they are on sale and learn to DO IT YOURSELF!It's not hard. A trained chimpanzee can do it!

  • OK firsti tried to write this so everyone can understand, so please bear with me, thanks.... I tell you what, i have a 2001 oldsmobile alero gls coupe with the 3400 V6, well my car is proof that synthetic oil is better and lasts longer, i bought the car 13 months ago, it had 100k when i bought it, i drove the car for about a month and i was averaging 13mpg city and 25mpg hwy, and then my change oil soon light came on, so i reverted to my trusty mobil 1 oil, well i used there best mobil 1 synthetic oil and which says its good for up to 15k miles, and a k&n oil filter i didnt go cheap the filter was about $17 and the oil was $32 for a 5 quart jug, $49 total, so i spent less then most people do at the dealer for their oil change, well anyways i noticed that the car had a noticable amount more of get up and go, and my fuel milage also went up almost instantly, averaging 16.4mpg city and 28.6 hwy, i always ran BP gas 89 octane (10%ethanol), never a drop of premium, so i know that doesn't have anything to do with it, well i kept checking the oil at regular intervals (every other week) at 10K on the oil it still looked brand new, i changed it anyways, and put in the same mobile 1 full synthetic and k&n oil filter, anyways i was changing it every 10k, always looked new, so the last time that i changed it was at 130K and i am now at 144200ish and i feel very comfortable with this oil and filter combo, i would trust it for another 5k.... And we all know how the GM 3100/3400 V6 had that stupid piston "tick tick tick", that for some owners, it started moments after they bought the car brand new and drove off the lot, well my oldsmobile which i know all the records on and it has NEVER had any motor work done, does not to the day go "tick tick tick" and i drive it a lot (of course 45000 miles in a year) and it idles a lot too, and also if i remember right conventional oil breaks down quicker and differently then synthetic oil, and here's the funny thing i've spent $200 for 45k worth of oil (4 oil & filter changes), k.. so the guy that follows his mantenence schedule of every say 4k oil change intervals and whatever oil and filter he chooses, we will say it costs $30 each time for him to change it himself, think its cheaper, not... it would cost him $330 to go the same distance as i did... see my point on awesome synthetic oils? but im not tryin to dog on the fact that automotive maintenence services (dealerships or repair shops), becuase 3000-3500mile or 3 months whichever comes first oil changes is preventative maintenence, especially with conventional oils and cheaper filters.... "Clean oil, Clean engine"... if i had the time to stop every 4k to 6k and change my very good oil and filter, i would... but what im doing now i feel comfortable with, not to mention this isnt my first car/suv that ive done this oil & filter combonation 2006 i bought a 2003 cadillac escalade esv, 6.0L vortec V8, AWD, 11mpg all the time cty&hwy when i got it, (31000 on the odometer), after changing the oil to the best mobil 1 synthetic and a k&n oil filter, i was getting 14.1mpg hwy and 12mpg city, in that big pig i saved some money it now has 251000 and runs great doesnt use a drop of oil, still getting 14mpg hwy and 12mpg city.... also in 2007 i bought a 1990 honda accord 4 door ex fully loaded, pw pl, ext. and a 5 speed manual transmission, i got the car at 185000mi on the odometer same oil & filter as the rest, city mpg went from 23mpg to almost 26mpg, and hwy mpg went from 35.1 to 39.7mpg, now i have almost 300k on the car and it runs great doesnt use any oil and still getting great mpg, and i have done this to a few other cars also, when i chaged the oil was different for each vehicle cause i drove them all differently... so my whole point is that you do pay more money for quality and i honestly think its worth it... thank you again for reading about how well this works for me, and i hope evryone understood it, hope this fixes some of the rumors and questions between conventional and synthetic motor oils....

  • yes it really does work, but conditions still do very, but i feel safe about this oil, also it does come dont to oil filters too, ive had the best luck with k&n oil filters, but puralator is i think the best if you want to stay under $10 for a filter, and fram is junk, garbage, i wouldnt even be able to count on my hands and feet how many people i know that put one of those frams junk filters on their carsand within2 to 3 days their engines were shot (spun bearings either crank or cam, and twisted piston rods), all because fram filter are way to restrictive on flow, and the cars all varied between 30000 and 200000mi, from 1 year old to 9 years old, they all including me tried getting fram to reimburse us for costs of repair, they wouldnt do it, why do you think that there isnt a single auto maker out there that runs fram from the factory? thanks guys.......

  • gordon942 gordon942 Posts:

    Daily driver 1997 Ford F150 pickup with 4.6 litre engine-4WD-auto that now has 331K miles on it-running errands-occasionally towing a horse trailer, picking up a load of firewood or mulch, picking up our Christmas tree, etc. and I always changed the oil and filter approx every 3-4K miles. Still have good compression-I own a compression tester!-and have never had an issue with the motor. Coincidence? Long ago, I bought a 1967 Olds Vistacruiser S/W with 330 engine at 180K and I drove it till I sold it at 320K back to the original owner for the original sale price? Again, changing oil and filter regularly and I did do a valve job-I worked at a NAPA store back then so I did the work-at 275K. It was a daily driver plus I used it to tow a race car. Coincidence?

  • dougde dougde Posts:

    I worked at a place that made motor oil additive. I replaced oil at every 3,000 miles. I took in old oil in to test it for sediment. 3,000 mile oil had a sediment level over 1%. All that sediment is in the oil wearing down the engine. Also acid byproducts of oil are neutralized by detergent in the oil which is basic. A change in oil is very inexpensive compared to the cost of a new car or engine. Therefore I always changed oil at the 3,000 interval and always had cars that lasted more than 100,000 miles.

  • "The Mobil 1 44976 Extended Performance 5W-30 Motor Oil is highly recommended. It gets great reviews on the web. Read more:"

  • chad_b chad_b Posts:

    2005 GMC Sierra..178,000 miles. The truck runs and drives like new..You couldn't even hear the thing run if it weren't for the 40 series Flowmaster. I use top quality (Royal Purple) synthetic oil and never exceeded 5,000 miles between changes. I'm no tech and definitely no expert but to me the proof of the benefit of using good oil and frequently changing it (along with paying attention to things like trans oil, gear oil and coolant) is right there every time I fire that truck up.

  • garagelady1 garagelady1 Posts:

    I disagree with the oil change recomendations that Edmunds sets forth for newer cars. Even Toyota has droppped their recomended intervals from 7500 miles to 5000 miles. Remember that most car owners stretch and foget to change their oil at any interval. Also the higher the mileage and the less miles driven per year does make a difference in the usage of oil and the longevity. Hence the 7800 mile rule is way over . Most car oweners than stretch that to 10000 miles. As a garage owner and engine rebuilder for more than 45 years, I can tell you even with the higher quality oils customers are very uninformed as to what oil is even put into their cars. And that reguent oil changes still are more than worth the money. Most used oil is recycled as our garage does we burn it in a waste oil heater. However be sure the garage or Jiffy Lube place you frequent is actually using the correct oil in your car and also be sure that they even change the il filter! Lots of cars come back to us with our oil filter still on the car even though it will have a quick Lube sticker on the windshield!

  • pccstudent pccstudent Posts:

    I was working for BMW when these long oil change intervals started (using pricy oil also).One thing we found in cars that were going the full 15K before a change was that the oil filter elements were turning to mush (BMW has a canister type filter)you had to clean out the caniater with a rag,the filter was just mush.BMW did fix this problem (this must have been 1998).Today there are problems with oil level indicators getting stuck and people driving low on oil.BMW is a company that does get right on these type of problems so I bet they laid this issue to rest also.

  • pccstudent pccstudent Posts:

    One issue I forgot to mention.If you want to start a never ending discussion where everyone is an expert (even those that never wrenched professionaly in their life) decide to make the subject of the discussion related to oil.Everyone is somehow,someway an expert on all things oil.

  • yrov yrov Posts:

    Don't listen to the Blackstone person in (5). I've done (5) to all my cars. The cars still drive like new after many years. The so-called break-in period is extremely important to all new cars to make (5) no myth. FYI, Mercedes-Benz owner's manual actually had one page on what to do in the first 1K miles and recommended service after the first 2K miles.

  • 8aa2ym 8aa2ym Posts:

    These generalizations are good advice. Perhaps an emphasis on knowing your own particular car, driving conditions and habits would be advisable. I only drive about 500 miles a month in a high-performance turbo-charged car. Most trips are less than 3 miles. I keep a close eye on her.

  • 8aa2ym 8aa2ym Posts:

    I'd like to see a few of us COMMENTATORS get jobs with Edmunds or form our own group. There is no substitute for being in the field. How were these tests run? Where is the data?

  • user3521 user3521 Posts:

    The only thing I like about using synthetic oil is after 50,000 miles or so, the inside of the engine looks brand new, no sludge or oil contaminant color.

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