Originally Posted By: Johnny2Bad
Oil and derivatives are only good for about six months from the well, so you are at the edge there. The problem is bacteria eats petroleum, and the bacteria is present at the wellhead, so everything is contaminated with it. Stored oils can get by because there is little to no air present in an unopened bottle, but fuel in a tank has a lot of oxygen exposure.
The bigger problem is probably that you are using winter gas, which has more aromatic compounds that evaporate better in cold ambient temps, which helps cold weather starts. So it's no surprise your fuel consumption is up in warm weather, some of what you are buying is gassing off while in a non-full tank. Things should settle down a bit when they get their next tanker fill of summer gas.
The fuel system cleaners are added either in the tanker when it fills at the refinery or is added when it fills the bulk tank by the driver. Generally speaking low cost fuel outlets don't buy it (it is expensive, relatively), relying on the base formula as it comes from the refinery. So you probably aren't getting whatever benefits they offer.
No, no and no. Gasoline is not affected buy microbial growth. Diesel fuel is. Fuel system cleaners are not an option for the gas station to choose. It is epa regulated and frequently tested. It is added at the distribution terminal.