1014 posts · Joined 2000. #2 · Mar 5, 2005. The bad thing about diesel is that it can collect water and grow algea. If you have used a cood conditioner like Power Service or Standadyn, you might be OK. If you can, draw some fuel out of the tank and look at it to see if there is any funk in there. MY TRUCKS. About one tank of fuel in an average car. Every 12 weeks you’ll get down to a quarter of a tank. So stop at the servo, on the way home, every three months, buy a quarter of a tank - live life on the edge. Mask up. Fill up. Keep JD Power Jessica happy - and her quaint oxygen evaporation hypothesis. Water, petrol and diesel though are a different story, with many travellers taking several hundred kilograms of them! Water weighs 1kg per litre. Petrol weighs 0.75kg per litre, and Diesel weighs 0.832kg per litre. Ideally, you want to keep the weight down as low as possible in a 4WD. 3. Where can I buy diesel exhaust fluid? Contact us or give us a call at 800-344-6457 for more information about keeping your DEF levels where they should be. 4. How long does diesel fluid last? Diesel exhaust fluid normally has a shelf life of about two years. However, exposure to sunlight or sustained high temperatures can compromise it. At this point, all you need to do is open the fuel tank, measure out the amount of stabilizer that is recommended by the fuel stabilizer manufacturer, and then pour this into the gas tank. It is a good idea to top off your tank at this point. If you can go with a gas that does not have ethanol, this is best. Filling your tank will help minimize The rule of thumb when replacing a fuel filter on an older model car is at least every 2 years or 30,000 miles. On newer models, this interval can run longer. The best way to tell if your fuel filter needs replacing is to have the mechanic do a fuel pressure test. This lets the mechanic know how much PSI the fuel pump is generating at the fuel Myth #3: “All STA-BIL products are the same, just different colors.”. To be blunt, this myth is false. Each product is specially designed to address and prevent a unique set of problems. STA-BIL Fuel Stabilizer keeps fuel fresh for up to 24 months, making it ideal for long-term engine storage. How long can gas sit in a car? Gasoline can last between three months and three years depending on the type of gas and if it is properly stored. It’s important to note while all gas will naturally begin to degrade over time thanks to exposure to oxygen (also known as oxidation), all gas is not created equal. But for the most part bad gas was a problem that affected people like farmers and antique car guys who let things sit for a long, long time then tried to take a shortcut by not cleaning the old fuel out of the tank or engine before they tried to bring some piece of internal combustion equipment back to life. That was the old days. How Long Will Gasoline Last? On average, gasoline will last and can be stored for about 8 months in a sealed container and 3 to 6 months in your car’s tank. Diesel fuel is rated for twice the amount of time, ranging anywhere from 6 to 12 months in the tank. Ezta.