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Gas quality

Have been advised by local GMC dealership, that I should NOT use Costco gas as it is of a lower quality. Any truth to this?


Yes. But that’s not limited to Costco and the differences are slight and most people will never notice the difference.

Your dealer may be remembering the GM Vortec injection systems of a few years past that were subject to plugged injectors, sometimes caused by the lower detergency of no-name fuels.

Costco, supermarkets, etc, buy gasoline on the open market from the lowest bidder. All gasoline must meet federal and state requirements for detergency, ethanol additives, octane, etc. But major brands all have their own brand of detergent additives–Chevron with Techron, etc.–that are proprietary and do help to prevent and remove carbon deposits better than the no-name gasolines. Some people swear that their cars don’t run as well on Costco gas and some people never notice the difference.

It’s like the difference between name-brand groceries and store brand. The name brand is probably better. But both will fill your stomach.

Do not listen to the counter help at the dealership service department.

On my way to the office every day I go past a fuel terminal. The Mobil, BP, Cenex, Citgo, and all the other brand trucks line up for the same hose. Talking to a driver one day he said in a 9000 gallon load he dumps in about a gallon of additive. I’m not convinced it makes that much difference.

BTW the fuel you get at Costco in one city is likely going to be different in another city. For that matter, it may change from month to month. In many areas the same trucks supply many different brands. They may or may not make adjustments to an additive package or octane as well.

I feel it’s about the storage tanks and the local safeguards in ensuring the gas quality was maintained. IMO, that can vary more from one station then one brand to another. Gasoline distribution is tightly regulated but that doesn’t ensure there will be no problems. I feel as long as there are high turnover rates from a reputable suppliers you’re OK as I I see the same trucks filling competing brands. My neighbor who has pumps at his store sees no difference from brand to another.

I agree that the difference is more about the quality and handling of the storage and dispensing system.

We have a brand new Costco gas station in our neighbrhood, and cars of all price ranges gas up. Costco is quite fussy about meeting quality standards. On the other hand, in an older part of town there is a lawsuit going on about an old oil company gas station with leaking tanks and poor housekeeping.

Agree with ok4450 that advice from any GM dealeship employee should be taken with a few POUNDS of salt.

Having owned a number of Chevrolets, I can recall most of the GM service writers being thoroughly incompetent, and even mechanics being puzzled by a leaking heater core, which anyone with a nose can properly diagnose correctly.

After having been humbled by bankruptcy and bailout, the arrogance (combined with ignorance) still has not disappeared.

Just to add some detail to my unusually brief, one-word reply above, if you bother to go to a Costco gas station, you will see that they mention (on very discreet, small signs), that they use 5 times the amount of detergent that the EPA requires. That most likely means that they qualify for the Top Tier certification, but knowing how Costco operates, I doubt that they want to pay the costs related to gaining that certification.

Having done business with them for years, I know that they hold their vendors to incredibly high standards, and they are also scrupulous about customer relations. As a result, I do believe that their gas is as claimed.

Yesterday, I filled up there–as I have for the past 8 months or so–thereby saving 32 cents per gallon over the stations somewhat nearer to my home. If you are tempted to avail yourself of their bargain-priced gas, here are a few things to bear in mind:

Just like with their pharmacies, you don’t have to be a member in order to buy gas (at least in NJ!). Membership requirements only apply to purchasing the goods in their warehouse section.
They do NOT accept cash or most credit cards. You can pay with your choice of an Amex card or with “selected” debit cards. Since I pay with my Costco Amex card (which gives me an additional 3% rebate on their already bargain-priced gas), I don’t know which debit cards are the “selected” ones.

“After having been humbled by bankruptcy and bailout, the arrogance (combined with ignorance) still has not disappeared.”

That wasn’t a GM representative, but a dealership representative. Given the size of dealerships these days, the owner may own several other non-GM brands. We might not get the same answer from a GM engineer that works in fueling.

I would not hesitate (and do not hesitate) to use Sam’s Club gasoline and have no problem with it. This would be similar to Costco gas.

I’m just an avg car owner that tries to care for his his car according to the owners manual and having just purcahsed a new 2012 Chevy Equinox V-6 SIDI engine, while reading about the reccommed fuel being ‘Top Teir’ really had no idea of what that was until I went on for some info. For me going to one of the recommened stations is no big deal because all the stations prices are within a penny or two of each other and also the manual says if you don’t use one of Top Teir brands to just add fuel injector cleaner at each oil change

Be aware that the EPA strictly regulates gasolines

The American Petrolium Institute has its own controls, as do other industry organizations, but the EPA’s standards are mandated.

I’m confident in stating that Costco gas is in full compliance with the EPA requirements. Especially since gasolines of different brands come from the same main supply pipe. The different companies pay in for the use of the distribution system by volume pumped. Costco may pump 10,000 gallons in and 10,000 gallons out, but it is not the actual same 10,000 gallons. As a matter of fact, different octane ratings are pumped through the same pipe. The system used to use “pigs”, plugs between the different octanes. Not sure how they do it now.

My criteria for buying gasoline was the type of trading stamps (S & H Green Stamps, Holden Red Stamps, Top Value Stamps) and whether the filling station gave you a free drinking glass for each 10 gallon or more fillup of the gas tank. Of course, this was 50 years ago. In my present cars, I have noticed no difference no matter what station or brand I use to fuel up my vehicles.

the same mountainbike

You wanted to know how the pigs/plugs work? They draw out of a tank what they want to send down the pipe. They put a pig/plug in front of it and one behind it. When it gets to where it’s going. They pull the pig/plug out into a tank(with some of the gas),then the gas go’s to its tank. You can have any oil product going down the pipe all separated by the pigs/plugs at one time.

I understand how pigs work, but I seem to recall seeing a special on PBS about how the gasoline distribution system worked and seem to recall them saying that they have such control over the fluid flows now that they can put 20,000 gallons of regular into a pipe followed by 20,000 gallons of premium and sithdraw them at the other end of the pipe as regular and premium just based on volumes moving through the system…without the use of pigs. I was (and am) reluctant to state that, because I can’t remember the details of the special. As I recall, the special was focused on gasoline only and did not discuss the use of a single pipeline for products other than gasoline.

I used to work around the pipe lines. I have been in the control center. I wont say its not possible to that. The pipe lines I was around had all products going down the pipes at the same time. I was told that pigs mix with whatever in front and in back of them. Thats why they are put into a separate tank to recover what was mixed in.

The part that’s between the 2 streams is called the “interstial slug”, a tech word describing that part which is diverted into a separate tank and goes back into the refing process.

There is one pipeline crossing th Rocky Mountains to the West Coast that tranmits gasoline, Avgas, diesel and kerosine for jets.

There are fewer and fewer (but much larger) refineries in North America, and the whole continent is criscrossed with “product pipelines”, those that carry refined products. Other pipelines carry natural gas or crude oil.

I just realized I’ve reached a turning point in my life. The price difference per gallon between two stations less than a mile apart can now be greater than the price itself was when I was growing up.

Hurts, huh?
I remember when the volume wheel on the pump spun faster than the total cost wheel.
I remember the “gas wars”, when stations were all full service and gave away free drinking glasses with every fill!

When I was in college, three things all cost the same; a tankful of gas for my 1948 Chevy, a case of 24 beers, and a decent bottle of whisky. All were $3!!! Now the beer is just over $20, the bourbon is about the same but the gas to fill a full size car is now over $65. I just gassed up my Toyota and forked out $46 but the guy with the Ford pickup rang up almost $100.

But then that 10 cent coffee is now nearly a buck even at Macdonalds.