Is Cheap Gas Bad for Your Car?

Is Cheap Gas Bad for Your Car?

Does Saving Pennies on Gas Put Your Car's Engine at Risk?


Gasoline is expensive and you're looking for every way possible to save money at the pump. You already shy away from premium fuel, knowing that your car doesn't require it. You'd like to save a few pennies per gallon more by going to an off-brand gas station. But you can't get rid of the nagging fear: Is the cheap gas going to damage your car's engine? put this question to experts in several fields, including an automotive engineer at a major carmaker, gasoline manufacturers and two engineers with the American Automobile Association (AAA). It boils down to this: You can stop worrying about cheap gas. You're unlikely to hurt your car by using it.

Because of the advances in engine technology, a car's onboard computer is able to adjust for the inevitable variations in fuel, so most drivers won't notice a drop off in performance between different brands of fuel, from the most additive-rich gas sold by the major brands to the bare-bones stuff at your corner quickie mart.

Still, spending a few extra pennies per gallon might provide peace of mind to someone who just purchased a new car and wants to keep it as long as possible. People with older cars might not be as concerned about their engine's longevity. They can buy the less expensive gas and still be OK.

Steve Mazor, chief automotive engineer with the Automobile Club of Southern California, summed it up this way: "Buy the cheapest gas that is closest to you."

Recipes for Performance — at a Price
But this doesn't mean that all gas is the same, even though it starts out that way. The fuel from different filling stations comes from a common source: the "base gas" from a refinery. Workers there mix additives mandated by the Environmental Protection Agency into the base gas in order to clean a car's engine and reduce emissions. Then, the different gas companies — both off-brand and major brands — put their own additive packages in the gas to further boost both cleaning and performance.

A key difference is that the major brands put more additives in their gas and claim to have some secret ingredients. This extra shot of additives provides an additional level of cleaning and protection for your engine.

But is this extra helping of additives, which jacks up the price, really necessary? And, if you don't use more expensive, extra-additive gas, how soon will your engine's performance suffer?

"It's not like any of the fuels are totally junk," says John Nielsen, director of engineering and repair for the AAA. "If you buy gas from Bob's Bargain Basement gas station because that's all that's available, it won't hurt your car," he says.

The real difference is the amount of additives that are in the gas, Nielsen says. More additives essentially afford more protection — but they also cost more.

Some automakers and oil companies believe that the amount of government-required additives isn't enough to protect engines. They have created a Top Tier gasoline designation. It means that those gasoline brands sell fuels that provide more and better additives.

Nielsen recommends that drivers look in their car's owner's manual to see what the carmaker recommends and, when possible, follow that guideline. People who are still concerned about gasoline quality can ask a specific oil company if it has performed independent testing to substantiate its claims.

Selling the Secret Sauce in Gasoline
The major oil companies spend millions of dollars convincing buyers that their gas is superior by creating ads that feature smiling cartoon cars, lab-coated nerds and sooty engine valves. Buy Shell's nitrogen-enriched gas, for instance, and you won't get a buildup of "gunk" in your engine, company advertising promises.

Is all this just a marketing gimmick?

"I am a Ph.D. chemist, a nerdy guy who wears a white coat," says Jim Macias, Shell Oil Company's fuels marketing manager. "We really believe there are differences in fuels. We can see it, feel it and measure it."

Macias says the gunk caused by fuels with insufficient additives can foul fuel injectors and even trigger "Check Engine" lights in as few as 10,000 miles.

But not everyone is keen to talk about gasoline quality and whether additives really make the difference.

Edmunds sought comment from one well-known seller of low-price gas: Arco. Arco also often finds itself targeted as being a lower-quality product. BP, Arco's parent company, did not respond to Edmunds' interview request.

The American Petroleum Institute provided background comments about fuel additives and promised to provide an expert for an interview. The API spokesman never called back.

Finally, Southwest Research Institute in San Antonio, an independent, nonprofit testing facility, also declined to comment on the question of gasoline quality.

The Skeptics and Their Tests
The Auto Club's Mazor was more forthcoming, and has some interesting results from a blind test he did on three samples of gasoline from both major and independent gas stations.

"We tested emissions, fuel economy and performance and we could not tell the difference," he says.

Mazor believes that the driving public has outdated notions about gas. Twenty years ago, only premium fuel had detergents in it. Back then, it was beneficial to occasionally buy a tank of high-test gas to clean the engine. Then, he says, "regulations were very lax and there was little enforcement. But all that has changed."

Likewise, Randy Stephens, chief engineer for Toyota's Avalon, isn't wholly convinced by the claims of engine protection afforded by higher-priced gas. He says fuel experts at his company study the effects of different brands of gas on the Toyota engines. Automotive engineers disassemble engines after 10,000 miles of running them on different brands of gas to see if there is a difference.

"Honestly, in the 10 years I've been in charge of Avalon, I've never seen one come back with any sort of deposit issue," Stephens says.

Nevertheless, Stephens admits to being "swayed" by ads that tout cleaning agents. Twice a year he adds a bottle of Chevron U.S.A. Inc.'s Techron — the same additive that's in Chevron gasoline — to the fuel tank of his personal car.

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  • empoweredbc empoweredbc Posts:

    I've seen major franchise brands put no-name brand fuel in their pumps. They'll hustle you just like the car companies, the government, Wall Street..... All that glitters is not gold, my friends.

  • kingon kingon Posts:

    If next five years or ten years if US popular will own new diesel vehicles will replacement to currently gasoline vehicles in gas station about if the gas station will both gas and diesel pumps.

  • bestjinjo bestjinjo Posts:

    This article is only partially true. If you have a car with a Turbo engine and the car's manual states that Premium gasoline is required, you will damage the engine if you use standard gas and create serious issues. Standard gas is perfectly fine for normally aspirated engines.

  • alex4515 alex4515 Posts:

    I've never had an issue with grocery-store brand gas and it's usually the cheapest around here.

  • fin442 fin442 Posts:

    The gas might be safe for engines but not for Fuel Pumps/Sending Units. The problem that this article overlooks is that stations buy gasoline from many different vendors. Different vendors use different additives (different for every company because they are proprietary) mix with each other and react like most chemicals and its not enough to hurt an engine but a fuel pump which is the size of a soda can with small metal and plastic parts it can be devastating. Cheaper gasoline will also have more sulfur content which can corrode and damage sending units making the Fuel Gauge inaccurate and dance up and down between empty and full. I have had multiple experiences with these issues. 1) 2003 Chevrolet Cavalier 2.2L Ecotec I4 had fuel pump die after refueling at WAWA and rolled to a stop on I95 near Philadelphia Airport. Was able to scurry to shoulder with help. 2) 2000 Ford Ranger XLT 2.5L SOHC died in driveway after refueling at WAWA. Both incidents happened within 3 weeks of each other. 3) 2001 & 2002 Oldsmobile Aurora and Intrigue both used WAWA gas and fuel gauges went crazy. When removed from Intrigue the sender unit had copper contacts that had been burnt and corroded.

  • carchatter1 carchatter1 Posts:

    Yes, all good info. Now can anyone please put this myth to the test about it being bad to gas-up when the tanker is there filling the gas stations tanks?

  • bankerdanny bankerdanny Posts:

    Bestinjo: you are confusing Premium (high octane) with premium brand (BP vs local brand).

  • eidolways eidolways Posts:

    I know that after using a lower-cost alternative for fuel repeatedly in my Subaru, it began throwing a "Cylinder misfire" code that was cleared up by some fuel-system cleaner. So in that instance, the fuel I was using seems to have promoted some build-up. However, my car had 175,000 miles on it at the time, so there's no telling how much build-up there already was, and the issue was fixed by a $5 bottle of fuel system cleaner. So I stick to the bigger brands when I can, but will also use the less expensive brands when I feel like penny-pinching and then just use a bottle of fuel-system cleaner on occasion to clean up any residue that may have been left behind.

  • greenpony greenpony Posts:

    I've never had a brand preference. After driving probably half a million miles in my life so far, the cheapest gas has always worked just fine.

  • dieseltc dieseltc Posts:

    The same subject came on Motorweek just the other week. They suggested staying away from off brand names. Not because they're bad but because fewer customers to the stations means that the gasoline in the storage tanks stay longer. Because gasoline evaporates, the longer gas is stored in the tank, the more gasoline evaporates minus the additives. This then results in a higher proportion of additives to gasoline which can cause harm to your engine, fuel filter and so on. A tip I was told years ago was to rotate through the different gasoline brands because even the additives can build up. Additives from one gasoline will see the additives from another gasoline as build up and remove it. Not sure how true that is...

  • hank72 hank72 Posts:

    Adding to comments about the stations themselves, as a recipient of two tanks of contaminated gas that messed up my fuel system, caution should be taken when deciding to save money by filling up at a station that you know has been around for 25+ years or a relatively new station with newer tanks and filtered lines.

  • sotolux sotolux Posts:

    I have had to replace an expensive fuel injection component on my GMC truck because of cheap gas. I will never save enough money using crap gas because of that expensive repair. Now after 10 years of long use, the fuel injection is clean and it still passes smog after all this time by using additive gasoline.

  • alfaduetto alfaduetto Posts:

    Nomally run 87 in my '08 Mustang GTCS. Tried 93 for several weeks and it got poorer mileage and stumbled and hesitated allot. I suspect the premium is not sold much and is probably pretty stale compared to the higher usage "cheap" stuff. True for both BP and Shell in the car.

  • davantriv davantriv Posts:

    So, the point of the article is that off brand gas doesn't damage the engine of a modern car. I feel that if this article had been posted in two years ago, it would have had a more scientific, methodical outlay to its conclusion. With the evidence from independent sources provided, there was really no point in dragging this article out beyond the "'Buy the cheapest gas that is closest to you'" statement.

  • miguelmgp1 miguelmgp1 Posts:

    chep gas is no bad for you car but if you car 20+ millas for 1 gallon of good gas is going too be 20- w/chep gas.

  • eric_l eric_l Posts:

    There is so much blatantly wrong information in the comments section of this article. The article itself is basically correct - gasoline is a fungible commodity and what gets transported from the refinery to the depot (where the fuel trucks fill up) is basically the same thing - it doesn't matter if it will go to a Chevron, Shell, BP, or Bob's Budget Gas. All the trucking companies that deliver fuel do so on a per load basis, and they don't care who they deliver to (the marking on the side of the truck is for the most part, meaningless) - depending on where they make their delivery, the depot will dispense whatever additional proprietary detergent package that the station requires. That's it. Any reports of "bad gas" or "low quality gas" has more to do with the quality of that particular station's filters and holding tanks than it does the actual product being delivered, since it is for the most part, identical to any other gas station save a bit of extra detergent. As long as you buy gas from a busy station, there should be absolutely no problems. As for Motorweek's "gas sitting so long it will end up concentrating detergents.." - take a minute to think about it. Is that really so dangerous? Chevron claims that adding a bottle of Techron concentrate gives you 10x the average techron concentration of Chevron gas, and that is obviously safe to run every 3000 miles (the limit is more to due to it seeping past the rings and diluting the oil, rather than what it could do the fuel system).

  • joliepop joliepop Posts:

    Interesting stuff here about Shell. I googled can cheap gas hurt your car and this article is the first that came up. I have a 96 Honda Civic that until recently NEVER EVER had any engine issues. I realize it's now vintage, but I have taken exceptional and preventive car of this car. I ran out of credit late last Summer and started putting Arco gas in my tank as I could get cheaper since I was now paying Cash for everything. Six mos later, I needed a tune up. Now need a new head gasket. I have crud build up in my brand-new radiator. I have 130k miles on my engine. I realize people will say oh it was just time for those things to fail. But I don't believe in coincidence. I just don't. I know my car, I know my engine and it went from purring like a kitten to staling, having bad starts, just issues that yes, may have happened in time. But I think a few cents more a gallon may have at least bought me more time before these things failed. I mentioned that my car seemed to hate the cheap gas to my mechanic a few mos after I started using it, and it was stalling, and he told me there is no such thing. Gas is gas, save your money. So I'm going to disagree with everyone. I realize the damage is done, but I put Shell gas in my car tonight and I will never put any other gasoline in my car ever again!

  • ortauto ortauto Posts:

    I've used Citgo for 30 years or more. I put 215,000 miles on one Ford, and 160,00 miles on another so far - with no engine problems. My son, using the same maintenance proceedures on his first two cars lost the engines a little over 100K. Son saved a few cents on each gallon using no name gas - but lost the cars. Engines completly fouled up beyound repair. Citco station changes filter once a week. No Name gas? I understand the major gas storage outfits sell the bottom of the storage tank to the No Names. You get what you pay for.

  • jbow614 jbow614 Posts:

    It seems to me that all gas stations charge the same price for gas as any other. If speedway is $3.39 then swifty, pilot, marathon, etc. are all $3.39 also. Of course you should not use premium if it is not required. If you're gonna pay the same price for gas no matter where you go then might as well get excellent high quality gas, such as "top tier" certified. Shell and exxon, and mobil are all top tier in my area. A cleaner engine is better than a dirty one. Why go cheap on the literal "fuel" for the second largest purchase in your life? Better performance, gas mileage, longer life and less maintenance is worth the same price, or if you must a "few cents" more. Cheap gas also lacks sufficient amounts of other additives too, not just detergents. And chepo gas stations usually don't have programs that let you save even more money per gallon, i.e. Kroger fuel points useable at the best quality gas carrier, SHELL! If chevron additive twice a year is good, how much better is concentrated techron every tank, along with the other high quality and quantity ingredients, i.e. stabilizers, anti-corrosives, lubricants, octane additives and not to mention the base oil.

  • jbow614 jbow614 Posts:

    The best thing overall is to buy the same brand of gas every time. Switching from cheapest brand to cheapest brand IS bad for your vehicle! it's common knowledge that BP gas sucks! Even tho it is now a top tier fuel. I recommend SHELL gasoline very tank fuel, and try to keep you're tank at least half full at all times especially in the winter to help avoid water and ice build up, and try to fill up at dawn or duck when its cool outside, as gas expands withe heat, you'll get more for your'e money. Find your nearest high quality fuel station and use that brand every time. To enhance fuel quality even more, use Motorkote Fuel Optimizer as directed. Meijer's has it. SHELL+MOTORKOTE FUEL OPTIMIZER = AWESOME!!!

  • cmmcd0472 cmmcd0472 Posts:

    Joliepop, I'm sorry but your friends and mechanic were right about things starting to go wrong at a certain age. My '94 Civic needed a head gasket at 130K. The type of gas you use has nothing to do with your radiator going bad but flushing and refilling at regular intervals does. I personally don't think there's much difference between Shell and Arco. Civics are good cars but between 130K and 150K they will start needing some work, and some of it depends on the type of driving you do (highway or stop and go). It may just be coincidence that you needed a tune up. Are you sure they didn't tell you that you needed a head gasket when you needed something else, you might have wanted to get a second opinion on that one. Cars usually overheat or blow white smoke from the exhaust if there are head gasket issues.

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