Is Costco Gas Quality the Same as Exxon, Shell and Chevron?

Costco gas quality
There are many reasons to love Costco. They treat their employees much better than many businesses, and they have competitive prices when it comes to the things that they sell. While there might be some reasons that you wouldn’t want to shop there, a lack of quality in the gasoline they sell is not one of them.

If you have ever driven by a Costco and looked at the prices at their gas stations, you know that they can be significantly lower than gasoline prices anywhere else in the area. It doesn’t take much to realize this. All you need to do is look at the long line of cars waiting to fill up their tanks to know that the price is significantly lower than most other places in the area. The prices can be so low, in fact, that you might wonder about the quality of the gasoline. When Costco is selling its gasoline for so much less than the competition, is it the same quality as brand-name gasoline such as Exxon, Shell, and Chevron? Most people want to know if Costco gas is good quality fuel.

The first thing that’s important to note is that the government sets fairly stringent standards for all gasoline that is sold in the United States. When it comes to octane level and other specific gasoline characteristics, all gas is basically the same. The difference between the fuel that you buy at branded gas stations comes down to the detergents that are added to the gas.

Even here, the government sets standards. The federal government has required since 1995 that all gasoline which is sold in the US must contain a certain amount of detergent additives. These additives are Environmental Protection Agency (EPA) approved, and the government has specified the amount of detergent which must be added to keep vehicle engines free from deposits. Costco gasoline meets all these requirements, or it couldn’t be sold in the United States.

The question then becomes, just because Costco meets the minimum requirements, is it still as good as other brand-name gasoline? A number of automakers made the decision that the US government additive requirement wasn’t high enough for many cars. As a result, they developed a “Top Tier” standard. In order to meet the “Top Tier” designation, the fuel sold at the gas station had to meet additive requirements higher than is required by the US government. Costco fuel meets this top-tier standard.

Is the gas that they sell exactly the same as the major brands? No. But no major brand sells the exact same fuel. Costco gasoline is rated as equal to any other major brand gasoline. You should not notice any difference when filling up your vehicle at Costco as compared to other major brands of gasoline. The only difference you should notice is the significant savings that you receive when filling up your car there.

Even if you feel that the gasoline isn’t quite as good as another major brands that you have used, you might want to try this “gas hack” that will still save you money. In most areas of the country you can fill up at the Costco gas station, plus add quality fuel injector cleaner that you can purchase inside the warehouse. If you add this fuel injector cleaner as recommended, you will still pay less when purchasing Costco gas, and the fuel injector cleaner, than you would by purchasing gas alone at a major brand gas station.

In the end, there is nothing to suggest that Costco brand fuel is inferior to any other brands of gasoline. Don’t let the price alone dissuade you from getting a great deal.

(Photo courtesy of Adam Keys)

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64 Responses to Is Costco Gas Quality the Same as Exxon, Shell and Chevron?

  1. joe says:

    Thank you for this informative article. I have wondered about comparison with other gas suppliers and this gives me comfort.

  2. Andy says:

    I have been told by those that drive trucks full of gasoline and deliver it to the different stations that it is all the same. Every company does not have it’s own refinery, but all companies use the same gas from the same refinery which goes into the same trucks and then is delivered to all the stations.

    An interesting question to ask would be has anybody ever seen a scientific study proving that one companies gas is better than anothers?

  3. Gas price is one of the major problems in our country. The gas hike continues to rise almost every week!

  4. Praising Costco says:

    That is true, however as a seasoned costco member and a 2013 hired employee, quality of all products has always been a concern and a personal mission of mine to research. Rest assured once the gasoline is onsite it becomes a top tier gasoline ( a Kirklands Signature ) and no longer generic and yet another genius process that sets Costco apart from the rest.

  5. Earl Richards says:

    To avoid the gasoline price rip-off, plug your Tesla S electric car into your household, solar array.

  6. mom-from-missouri says:

    Interesting. First husband and I owned several gas stations back in the 80’s thru 2008. We changed branding several times–Phillips 66, Conoco, BP. Yet, it all still came from the same supplier–Carter Petro….same truck same delivery driver….
    He would top off our tanks then drive down the block and top off the next stations tanks.
    It is all the same stuff.

  7. Praising Costco says:

    The process occurs onsite at each gasoline drop and at every Costco gasoline fill up site and that is where additional detergents while closely monitored by EPA are added. I am sure Costco has invested a lot of $ by doing this however as you can see it apparently has paid off. I am a costco employee .

  8. noah says:

    Yes they do all deliver the same base fuel as addattives are usually added and mixed at the retail station, the addatives are what distinguish one brand of gas from another.

  9. michael reed says:

    I work for costco In eugene oregon and was a gas station employee. Costco gas is truly everything they say it is and the additive we add with every load coming in is truly top quality. Costco is all about value and top quality products and I’m proud to work for a company that treats it’s employees so well. A+

  10. Carrie says:

    I beg to differ. I love Costco, I shop there weekly but several years ago I had many car problems. My car was at the dealership week after week thankfully all covered within my 36,000 mile warranty. It was later discovered that the cause of the nearly $5000 of damage to my 3 year old car was Costco gas. Once I stopped filling up at Costco I only went to the dealership for regularly scheduled maintance. Many dealerships such as Mini Cooper reccomend to their customers that they not use Costco gas. I assume BMW says the same since they own Mini.

  11. MikeH says:

    The worst Gas in AZ and you can tell from 1 fill up. is AM PM…. I do not notice a difference between QT and Costco, but sad to say QT is same price usually and NO Lines…. Would love to go costco more,,, but I leave for work by 5am,,, Costco CLOSED, QT is open,.,,,

    Next other time,, you already have a self serve,, make it open 24 hours… Duhhhhh

  12. Doreen says:

    Just recently costco now sells tier 5 gas which is higher than chevron or shell based on additives.

  13. Yeah boy! says:

    Mom’s comment is probably one of the most valuable in the discussion of gasoline quality. First hand, real world consumer type of comment. Scientific and brand-biased comments don’t really help when we just want an answer that cuts to the quick. No clutter. No confusion. Thanks, mom-from-missouri.

  14. Holly Nelson says:

    Might want to reconsider Costco. Are you Pro-America like the rest of us, or Anti-America like Costco?

  15. Merica! says:

    Holly… don’t be a troll.

    I stand for American Workers, and that’s who Costco takes care of.

  16. JB says:

    I had the same problem with my BMW 745. Warranty repIred at 5,835. They also told me to stay away from Costco. All i ever used is premium, even at Costco. It took about 3 monyhs and my troubles began.

  17. Vv says:

    I also like Costco and frequently shop there. However, I stay away from their gas stations. My 2006 Nissan Altima started giving 19 mpg on highway which should be 27 mpg under standard operating conditions. Engine vibrations also increased significantly and the drive got rough overall. Once the “check engine” light turned on the first thing I did was changing the gas company. Within two days after changing my gas, the “check engine” light went off and the gas mileage also improved (27.7 on hwy, 25.4 city). It runs smoothly as it did before I became a Costco member and started using their fuel.

  18. Scionxb12 says:

    Kirkland Signature gasoline, is the best possible gasoline money can buy. Gas is all purchased from the same suppliers but then they add 5 times the epa regulated detergent to their gasoline a major benefit for their members. Costco has very strict regulations on their gas they change their fuel filters more frequently than all other stations. Fuel filters are just like oil filters trapping sediments and particles and need to be changed every two months to ensure the cleanest product. Peoples comments are so funny on here the whole BMW’s malfunctioning due to Costco gas is a joke. BMW just wants to point the finger at someone else when everyone knows there cars are overpriced maintenance prone. If their gas was so bad why would they be praised Ford and GM that makes no logical sense. M.y mileage with ks premium improves 4-5 mpg city and 6-8 highway. Costco has the cleanest station around in my town. Even after storms they are out there making it sparkle. My rule of thumb for gas is if the station is dirty I wouldn’t trust the product but if it’s immaculate you can bet the product is just as clean.

  19. LCH says:

    Both my husband I started buying Costco gas around the same time. We have a Chevy Truck, and mini van. Both started having engine problems around the same time, and my husband, who is very knowledgable about cars, and repairs ours, believes it was the Costco gas. There is something different with this gas that causes problems! We no longer buy their gas, and have had no more problems.

    We figured out that by using the Exxon Mobile gas card with 6 cents off per gallon, plus some of the Mobile stations give you the cash price with the card, so that’s 16 cents off per gallon – better than Costco and no lines! 🙂

  20. Doo-dah says:

    It’s spelled additive and it is added at the terminal not the retail station.

  21. QT says:

    Doo- Dah
    This isn’t a class rm. if you feel the need to be superior go back and teach second grade. Douche- bag.

  22. ab14 says:

    Your CEL probably came on for a gas cap evap failure. I was driving to the vet early and got a CEL in my Is300, pulled the fuel cap, gasket was good so I put it back on (like you do at a gas station when you’re done fueling) and after the cars computer retested the evap system the CEL went off. I don’t blame the vet and ive never had any issues with my cars at Costco, not my Honda, nor my Lexus, not even my Ford. I think a lot of you have other issues with your cars and should invest in a set of tools and do some homework. Gas is gas and if you don’t maintain your car its going to stop getting good mpg, and its going to get deposits. I haven’t heard of fuel causing a CEL and I work in the automotive field…

  23. ab14 says:

    Im interested to know what code your CEL came on for.. never heard of gas tripping a CEL

  24. ab14 says:

    you should reconsider all the china made junk sold everywhere and the places that hire illegal immigrants to cook and clean, there’s a guy that tries to protest Costco fuel, the genius drives a eropean car. he must have gave up though cause I never see him and im there every time I need fuel

  25. ab14 says:

    lol how old are you, still calling people “douche bag” as a comeback

  26. Oz says:

    In summer this year we bought two new cars Lexus E350-2014 (wife) and Infinity Q50-2014 ( me). Both are rated at 20miles/galon for city drive. We use Costco premium 91 gas in both. In practice Lexus yields about 18.9 miles/g but so far Infinity Q50 yields only 15.3 m/g. I reprted the disappointing milage to the service manager. She suspected gas brand and advised not to use Costco gas (old gas ?). I do not understand it since Lexus E350 milage is close to stated rating with the same gas brand. Both cars are driven in the same city and route. I wonder if Infinity has over stated its fuel economy similar to reported reported in news about an other car maker. Infinty Q50 is a new model that came out in 2014 so there is no prior history of fuel economy.

  27. Jose says:

    We have a 2011 Ford Explorer and i have been using Costco gas exclusivley. Im averaging 17-19.4 miles on the highway communting work. We averaged 24.9 when we traveled to Santa Barbara and Monterey, Ca. We stopped at a few at Chevron stations ( 2nd choice) and i found both give me the same results. So far, i have been happy with the quality of gas from Costco. Im really picky and i meticulously take care of both my car and my wifes honda Civic.

  28. JamesG says:

    I’ve been running pure Costco Gas on my 2014 Mazda6 since day 1, when I bought the car. No other gas station brand. Be it regular or premium Costco gas I use (premium is now only $2.74/gal, as of this writing) as my car’s direct injection engine was originally designed to run on premium (slightly better level of detergents). Costco gas is Top Tier gas and runs perfectly on my car. Being knowledgeable on cars, and as a preventive maintenance, I pour a bottle of Chevron Techron DI cleaner twice, every 5,000mi, since the car’s mileage hit the 10,000mi mark (also from inside Costco). I have no problems at all, since Day 1 of Costco Gas use on my Mazda, whatsoever.

  29. The coke guy says:

    I’ve owned Nissan Infiniti Mazda Ford and Scion. And I am hear to tell you the Infiniti and Nissan (same company) are never close to what they say on the mileage. Idk how they test but it’s about 7 miles off what the say

  30. Lexie says:

    Since gas has dropped below three dollars I filled up my tankwith Cosco gas which I always buy. However my car gas mileage average suddenly dropped from 22.5 around town to 17. What is with this?

  31. douglas says:

    If you have always bought it in the past and it just dropped this last time, you need to take your car into the mechanic. It’s likely there is something wrong that made the gas mileage drop.

  32. Roam says:

    First… Getting repairs done at any car dealership is a rip-off, they overcharge on everything (parts & labor). It is only worth going to the dealership for repairs as long as your warranty covers it all.
    Second… You get what you pay for. Generally cheap gas is low quality, when it comes to cleanliness.
    Examples: Shell gas is rated the Cleanest gas in the USA, by the EPA. Some Sunoco stations sells the highest octane, which means you get more power for the engine (basically it is the lowest of racing-fuel that is street-legal). BP has a higher Ethanol% than other brands.

  33. brad says:

    Except that it has been computed, many times, that the excess purchase price of those vehicles, when extrapolated using non electric cars in comparison, end up costing more. (With the exception that if you keep the car more than 7 years, then it will cost less overall, than a standard gas vehicle.)

  34. brad says:

    While this article is “generally correct”, it errs in that I ALWAYS find a local retail station at the same, and usually, lower price as Costco. Usually, but not always, ARCO.

  35. Jim says:

    I’ve enjoyed the discussions on this post, and would like to clear up a couple of points:
    1-All retail gasoline comes from the same refinery. The difference is the additives.
    2-Companies like Shell use a dedicated truck to deliver the fuel from the refineries. (Usually contracted from a local deliverer.) Before the truck leaves the refinery, a Shell employee will pour 2-4 gallons of their additive into the fuel tank. By the time the truck gets to it’s first station, the additive will have mixed evenly through the tank.
    3-About 5-7 years ago, Costco decided to upgrade the quality of their fuel. Because Costco doesn’t have a lot of stores, they don’t hire a dedicated truck to deliver the additive. Instead, they have an onsite pump that injects the additive with the fuel.
    4-The name brand fuel companies (Shell, etc.) are constantly experimenting and changing their additive formulation. This means that what you put in your car today is different (and hopefully better) than what you put in your car last year.
    5-Time of day/temperature has very little impacted on the density of the fuel you get at the pump if the tanks are below ground. This is because the below ground temperature is stable, and is about 3-months behind the above ground temps. Above ground tanks are more susceptible to temperature fluctuations, and could result in a higher density of fuel in the early mornings.

    My qualifications: I am a former petroleum manager for NATO troops in Afghanistan. My training includes refinery operations, inventory management through temperature controls, and retail operations.
    I have kept this post simple by leaving out issues like: Summer vs Winter Fuel, fuel agitation, flash point suppression, premium vs regular, etc.

  36. Brian Turner says:

    Today I bought gas at the Simi Valley, California Costco. I could not start my van after filling up, despite many attempts. I thought it was vapor lock. So I removed the gas cap. Then my van started. Later that day after using up most of my gasoline, I attempted to start my van. Usually my van fires up instantly. But again I had trouble starting it. I drove to Shell and filled up. And presto, my van fired up immediately. VERDICT: Costco gas has way to much ethanol added for current vehicles, and should not be used!

  37. Justin says:

    You do know that when you fill up the gas you just put in the tank is not going to be the gas that goes through your fuel pump, through your lines, and straight to your engine? You still have residual fuel in your injectors, lines, and fuel pump from your previous fill up. You most likely have a separate problem with your vehicle and should have it checked out.

  38. konrad says:

    Time will tell… jist fueled up a 95 crown vic and i could only pull 325km out of it with costco fuel… where as with petro i get a minimum of 500 in city… fueling at petro today we will see in a week if the car has aged horribly or if there cutting corners.

  39. Mary says:

    I’ve always found the Costco gas quality to be the same as the top name brands of gas. Shell, Exxon, Chevron, BP. I keep a log to track the mileage of my car and there is no difference when using any of these. Since that’s the case, it makes sense to choose the gas that is the least expensive to get the best value.

  40. Cindy says:

    can too many additives cause issues? My car never seems to run as well on Costco gas as it does on other brands. Maybe I’ve just had bad luck?

  41. ColoradoRick says:

    I have long been a Costco member and use their gas for a Honda Accord, and VW bug, and my Range Rover. I started having issues with the Rover. I changed brands on the Rover and the issues went away. Not sure why it started having trouble but it definitely seemed related to Costco gas.
    The Honda runs fine but knocks on occasion, when that happens I just put a tank of some other brand through it and it clears up. Strange.
    The VW seems just fine with the Costco brand.

  42. Lanna says:

    Why do so many people seem to think that Costco gas is worse than other gas? It’s all the same stuff, fools. The only difference is the detergents in it. If your car runs badly on Costco gas, it’s the car’s issue, not the gas.

  43. Tauna says:


    As each car is different check your MPG. I don’t go to Costco because I loose 3 MPG while driving,or 30 miles per tank. I check different stations to see what fuel gives me the best mileage per gallon; Costco gives the worst MPG in my Hyundai.

  44. Joe says:

    Thanks for the info. Could you write a note to further explain the items you left out. I appreciate the info.

  45. wstrnrefinerysucks says:

    Clogged fuel filter in my Tahoe . . . also, clogs the fuel injectors to the point I have to put an additive in the gas tank. Chevron, Phillips 66, or Texaco do not cause the problem in the least.

  46. saikanomie says:

    Thank you mom. I would go Costco from today, and perhaps add my own additive from walmart.

    Octane booster

  47. Martin says:

    I work at costco and theres no filters at the gas station that get changed. I know cause I used to work at the costco gas pumps.

  48. James Adduci says:

    My question for Costco is, “How much ethanol is in Costco gas?
    The reason I am asking this question is because I was just given a 1977 Honda Goldwing motorcycle that is beautiful, but not running very well. I did some research on motorcycles and the new fuels with ethanol in them and it doesn’t look to good for any motorcycle. It doesn’t appear that the motorcycle manufactures have stayed up with the automobile manufacturers in preparing their products for the use of E10 or E85 gasoline. Also, these new fuels with ethanol in them need to be used at a fairly rapid rate or they deteriorate in power and sometimes separate in the tank under certain circumstances, such as in the tank of a motorcycle that is only ridden infrequently, like I do.
    Can you elaborate on this problem? It sounds like our government is interested in cleaning up the environment, which is good, but many motorcyclists are going to be upset when they find out why their bike is not running very well.
    Jim A.

  49. gary says:

    I had been a loyal costco gas customer until three weeks ago. within less than 100 miles of filling up at Costco, my car would not start and had to be towed into the dealer. After inspection it was determined that the fuel filter was so clogged nothing would get thru. After replacing the filter and cleaning the injectors we were back on the road. According to the service tech, he’s seen several cars come in on a hook after purchasing gas at Costco and he recommended steering clear of them and other low end suppliers. The couple pennies you save aren’t worth the inconvenience of having the car towed or the risk of engine damage.

    BTW, we spoke with the manager of the store where we used to purchase gas and he was “shocked” that we had a problem, since he had never heard any complaints before. We also filed a claim with Costco to cover the towing and repairs but were summarily denied.

    Lesson learned.

  50. Person says:

    Personally, i stick with shell when there is no costco nearby or they are close (because they are dumb enough not to have late hours at their pumps) jk …

    Whenever im broke or there is no top brand around.. ill pour in valero or arco … and boy it makes a huge difference you can totally make the test your self .. i mean just for the sake of your vehicle.

    Try driving empty to you favorite gas station (whether its cheap or expensive) to fill up a few gallons then drive of to u can tell u have spent those few gallons.. but meanwhile notice your engine power, speed and all that and of course your mileage… then do this as many times as possible with the same weather and road conditions and you can easily compare how cheap… means cheap.

    Then will stop wondering if really shells price its worth those 10 extra miles you can get out of filling up with them but that arco doesnt seem to work well on your engine.

    Personally costco is not top brand .. i get less millage when filling with them … but the price difference its pretty much as if you would fill up the tank with shell

    Engine wise.. costco premium feels good on my engine. doesnt shake like arcos or valeros gas.

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