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Costco gasoline

A friend’s mechanic said his engine (the valves) was in need of repair because he used Costco gasoline, which he said had high sulfur content because it comes from Alaska (and that Union 76 and BP have the same problem). This seems so unlikely to me, since refined (unadulterated) product should be equivalent to each other (besides octane rating). I thought I heard on the Car Talk program that Costco or other non-oil company brands all come from oil companies any way (Cheveron, Union, BP, Exxon, etc.). Could Costco or other non-oil company brands (like 7/11) be inferior to the regular gas sold by those big name companies? My friend’s car is a Toyota Camry, and the valves are all gunky per the mechanic due to poor gas. Do you think it’s the gas or something else? Can you tell me where Costco gets its gas? Doesn’t refining create a uniform grade or engineering standard?

Another urban legend. It seems people genarally prefer to believe nonsense more than facts.

All gasolines have to meet federal standards for various impurities as well as octane and other qualities. By the time Alaska oil is refined into gasoline, it is unrecognizable from the feedstock that went in.

Your friend could have ruined his engine by using regular gas when premium was specified. He also could have broken his timing belt on an interference engine, etc. Your friend needs a new mechanic who does not make up things. For all I know the mechanic adjusted your friend’s valves TOO TIGHT, and as a result burned them!!!

It’s impossible to tell where Costco gets its gas, since a Florida Costco station will definitely get it from a different source than one in Chicago or Seattle. It is not really important where the Costco gas comes from; the turnover is very high so that the gas is always fresh!

And you are right, the refining process takes out the sulfur and creates a uniform final product!

I think someone is blowing smoke. So exactly how did they determine “the valves are all gunky”? Remove the cylinder heads?

IF the heads have been removed and IF there is gunk behind the heads of the intake valves this is more than likely due to some oil consumption from around the valve seals.

I agree w/Doc, that Costco’s gas come from the same refinery as the other gas stations in the area, just with a different additive pack, but no different in sulfur content. It may come from Alaska, but so will the other gas in the area. How does the mechanic know the ‘valves are all gunky’?

Depending on the engine, some Toyotas were known for sludging oil, this might be another likely diagnosis. But, we’d have to see pictures of the engine tear down to be certain(but even then…)

Thank you for your response. Do you know if Costco has its own engineers test the product as it arrives or do they rely on certification from the supplier? It seems the supplier would really have to be nuts to give Costco any product that was inferior.

This is not an urban legend because I’ve taken engines apart and found the intake valves with heavy carbon deposits. These carbon deposits form when gasoline from the injectors comes in contact with backside of the hot intake valves. If you use a gasoline that doesn’t even meet the minimum standards set by the EPA for detergent additives these deposits can form. This is why they’re coming out with This gasoline not only meets the minimum standards set by the EPA but exceeds it.

When gasoline is ordered from a refinery by any gasoline company, the gas itself is removed from the main storage tank, but the additives are added later. So one gas station may order a load of gas with XYZ detergent additives, but the gas station across the street may order a load of gas with just the X additive. So one gas station will have more detergent additives in it’s gasoline than another gas station.


Problem with toptier fuel stations is that they’re not always close by, and might not even be worth the trip to go there

There is such an animal as top tier gas, but I don’t think gas is the problem. How often is the oil changed? Has the car ever overheated? Is it used always for around town short trips? Costco gas shouldn’t be that different than most any gas you can buy.

So from what I understand so far, the sulfur and octane rating and other characteristics have to meet standards, and that there are some measurment methods that make the standards reliable, but that the other cleaning additives are the real source of differentiation amongst gasolines, regardless of the original source of crude or the refiner. Cleaners are where the difference may be. It also seems that gas refined to standard is a solvent by itself, and that additives make it more so. Other problems with oil, engine temp, valve adjustement, etc. are more likely to cause a problem than the gasoline (assuming it is refined to standard).

When intake valves have heavy deposits, it’s ALWAYS the result of additives in the Motor Oil building up on the valves. Unleaded gasoline leaves virtually no deposits regardless of its source. Lets take Denver… There are two refineries in Denver, both owned by the same company, Suncor (Sun Oil). Virtually every drop of gasoline sold in Denver is produced by these refineries, regardless of the brand name posted on the pump. There is not a single Sunoco station in Denver… Oil companies have “Exchange Agreements” where they trade product amongst themselves to create the illusion of competition…Costco buys product on the “spot market” and in effect becomes a refiner who then can trade product with the oil companies. The product being sold by Cosco will be identical to the gasoline being sold by the “Major Brand” dealer down the street. You think every oil company has their own secret additive package or that one adds more detergent (or whatever) than the other guy? Do you think Shell’s “Nitrogen” marketing campaign is anything more than hype?

At the moment, I have two high-mileage Crown Vics…They are fed nothing but the cheapest regular gasoline I can find, including Cosco…They have never had any valve or injector problems, no CEL’s, no new catalytic converters…Gasoline is gasoline, it’s as simple as that…

I have been confused about gasoline and its additives for years. Shell gasoline had TCP. A chemist told me that stood for tricallo-tricreso-phosphate. My neighbor, who worked for Standard Oil told me that TCP really stood for Tom Cat P___. D-X gasoline had boron, or super boron or something like that. Apparently that is an element discovered since I took chemistry when the only elements we had were earth, air, fire, and water. American oil products had M2PG–I never knew what that stood for. Sunoco gasoline had a bluish tinge–could that have been a copper sulphate compound?

The cars I owned back in those days didn’t seem to notice what additives happened to be in the gasoline that went into their tanks–the performamce and mileage was the same. The cars I own today (2003 4Runner and 2006 Uplander) run the same whether I put in the least expensive gasoline I can find or the more expensive juice.

Maybe my vehicles just take on my personality. I buy whatever beer I can get at the lowest price and I do just fine. My cars seem to do o.k. on whatever goes into the gas tank and even my dog doesn’t complain about house brand dog food.

My brother in law in TX has several trucks and he delivers gasoline. Name brand or mom and pop stores; it all comes out of the same tanker.

The crud I’ve had to wire wheel off of intake valve heads while performing a valve job was oil based.
What I would like to hear from the OP is how this “gunky valves” diagnosis was arrived at.
Without cylinder head removal; BS.

I live near Buffalo NY and as far as I know there is not a single top tier gas station within 50 miles, the closest on may be 100 miles away.

I think there is a Shell station in Delaware and Upper Sandusky, but that’s a good half hour drive one way to get to it.

I put Costco gas in my car today. I had no problems with it before that, and had the battery changed about 2 weeks ago. Right at the gas station, the car wouldn’t start. I have never had this problem. It took me three times to get it to turn over. I forgot about it until I jumped in the car again later and it happened again! I called the dealership and they told me that I am the 5th person that has called with problems like this related to Costco gas. He said that my problem is so far pretty minor compared to others. He said that he has had to repair valves and has had to pump the gas out. He said that each company has a different blend and that whatever it is in Costco’s recent gas in the Chicago area has clearly got a problem. He even recommended that I just let it run and burn off the whole tank ASAP to get it out of my car as quickly as possible, but I hope I won’t have to go that route. Not only is that not particularly environmentally friendly, but I paid $46 for that tank! He told me never to use it again as it will create engine problems for me. I have an Acura MDX. I am going to email them.

Costco does not need to test the gas they buy, or any other product they sell. Gasoline quality is determined by federal standards, and Costco has enough buying power that no oil company would try to sell them an inferior product.

They have a very high turnover which means that the product is always “fresh”. Their tanks are relatively new so you don’t have to worry about contamination by rust.

Our family spent $8000 at Costco last year (buying a wide range of products) and there was only one item I bought in the past (3 years ago) that did not live up to its claim, a desk lamp made in California. They made a refund and no longer carry this product.

In France 45% of all gasoline sold is by grocery stores and department stores. Nobody worries about the quality.

If there is a problem with your valves it is not Costco’s fault, but could be lack of regualr maintenance, or your mechanic could have damaged them.

You should stop worrying about Costco gas and start with a new mechanic to get you car in shape.

How could Costco gasoline be the cause of the problem if your car would not start at the gas station after purchasing that gas?

At that point the Costco gas is in the tank. The gas that’s in the fuel pump, fuel lines, injector rail, and injectors is the gas you drove in with.

You should always take anything a service writer or service manager says with a lump of salt because few of these people have any mechanical aptitude at all and they do have a tendency to say things that are off the wall at times.

THOUSANDS of people filled up at Cosco today. If there was a problem with the gas, they would ALL be breaking down Coscos door with TV news trucks doing live shots…

People need to visit a tank wagon loading rack and watch the fuel tankers being loaded. Then follow the trucks to their delivery points. Same loading rack, a dozen different brand markings…

Different additive packages according to brand?? The only people who know that FOR SURE are the people who run the loading rack and they are not talking…There is no magic in gasoline. Just some detergents to keep the injectors clean. ALL retail gasoline contains those detergents. All by itself, unleaded gasoline is a powerful solvent and cleaning agent. It needs very little help in keeping engines clean…