pjinca

+1 agreed, if you live where gas stations see a greater variety of traffic you are less likely to have a problem.

NYC530XI

A quick google search yields a decent article on how and why gas can go bad (as much as I dislike CNN, I will link it :

http://www.cnn.com/2008/LIVING/wayoflife/0....gas/index.html

Oxidation I think would be the biggest problem. What do others think?

jm545i

+1
Top tier fuels

pjinca

I agree, especially in rural areas and areas that have not changed the laws yet. When I was in high school the City of Denver changed their laws to require that all gas stations change their fuel tanks when they discovered oxidation and the fact that older tanks were leaking fuel into the soil contaminating it. I am sure there are many areas of the country where they have not changed the laws or rules to modernize the stations.

txag_530i

"Rot" is probably not the correct word to use. When gasoline sits for awhile (30-60 days) then some of the chemical components can evaporate leading to less power for the engine and increased contaminates in the fuel.

Here's a pretty good article about what happens: Does Gasoline Go Bad?

NYC530XI

Wonder how many gas stations actually obeyed that law... Most likely none

The truth is most gas stations will sell their inventory, regardless of condition. Unless major gas companies have a buyback program for obsolete gasoline, which I highly doubt.

pjinca

Actually most did, they had a time frame to comply or lose their license, I worked at one when I was in high school and they did it as soon as possible (they saw it as a selling point, Coloradans can be as freaky as Californians when it comes to protecting the environment).

Have to agree on the second point, gas stations will sell their inventory regardless, because even if the gas companies DID have a buyback program - how would you get it out of the tanks? It would take forever to pump it out of the gas pump into a tanker, and siphoning won't work either.

z06bigbird

The BMW dealer is the first to accumulate a ton of info re bad/wrong gasoline. I follow their recommendations. My caddy had some starting problems a few years ago. Caddy dealer recommended that I avoid Sam's gas. Problem cured with a few tankfuls of another brand.

Dealer does not just pull a gasoline brand out of the air.

MIK_82

I have been using Sunoco 93 for 3 yrsnow... no problems yet.

wspinks

As a gasoline retailer and a E60 owner I think I should chime in here. The facts are that gasoline does degrade over time. However, nearly all gasoline retailers have much smaller mid-grade and premium tanks, and refuel it at about the same interval as regular. It is a very easy thing to control, because the % of mid-grade and premium sales to regular unleaded is almost exactly the same everywhere in the US. It is usually 10% of the total regular volume. So, most retailers will have a 10,000 gallon regular tank, and two 1,000 gal tanks for mid and premium. This is just an example to keep the numbers simple. Tanker trucks have several different compartments, and we usually load and deliver all three products at the same time. It would be very bad business to sell old, degraded gasoline to customers, just the same as it would be to throw the old, expensive, product out. So, as business people we choose not to do either of those. There are people that probably don't care as much as we do about this, but I assure you that those people are not usually in business for long, and those are not the type of gas stations that you are pulling your $45,000 BMW into. I hope this has been helpful, and please feel free to ask me any questions.