Fuel? Shelf Life? These two do have a relationship, and its vital to understand them when storing a fuel-powered vehicle for an extended period of time. Typically speaking, petrol straight out of a Bowser will have a a healthy useable life of approximately 6 months. This is a generalisation, as the freshness of the fuel can vary depending on its life before the Bowser, and also its subsequent life in your fuel tank - however using a 6 month rule of thumb is probably best practice for most.
What Happens After 6 Months You Ask?
Great question! 3 things tend to happen:
1. Lighter Hydrocarbons will start evaporating (A Hydrocarbon is the chemical result of oil going through the refining process), which means the compound of the fuel will be compromised, and won't be in the form it was originally designed for.
2. Once the lighter hydrocarbons begin to evaporate, remaining hydrocarbons can react with the oxygen in the tank and begin to form a solid gum-like compound. This matter can 'clog the arteries' of your fuel system, as well as block up filters and compromise fuel pumps. Not to mention it not being healthy for the running of the engine!
3. If the tank is only partially full, condensation can build up within the tank, causing oxidisation and compromising the performance and integrity. of the tank.
Doesn't Sound Great - How Can I Prevent This?
If the car is remaining in storage between 3-6 months, ensure you fill the tank to the absolute maximum. This will minimise the amount of oxygen inside the tank, reducing evaporation and condensation.
If you are leaving it in storage for 6 months and beyond, fill up the tank (non ethanol fuel if you have a petrol engine), and add a good fuel stabiliser. We recommend Penrite's version, which not only keeps the fuel fresh for up to 12 months, but also helps clean the entire fuel system.
But Wait, I have a Diesel?
Diesel is generally a bit more robust than petrol, but regardless we recommend the exact same procedure as what is detailed above. Good news - Penrite also make a Diesel Fuel Stabiliser
PS. Keep Your Fuel Cool!
This one is obviously a bit tricky, especially if you live in a hot climate, or are forced to park your car outside, however heat does accelerate fuel deterioration! Parking or storing your car in a dry, cool place will likely prolong the life of the fuel, as well as several other components of the vehicle, including fluids, tyres and other perishable items.
Fun Fact: In high performance/motor racing practices, some cars even feature fuel cooling radiators!
Disclaimer: Whilst we might claim ourselves as being vehicle storage experts, we are certainly are not claiming to be mechanical engineers! Always, always, always consult your vehicle manufacturer before using a fuel additive, and ensure if you do apply an additive, that it is suitable for your vehicle!