crayb wrote:We are having 15-20 degree mornings here in Central Mississippi USA and I heard my local news channel saying not to fill your fuel tank but stop at half tank to prevent condensation in the tank (?) Can't say I've ever heard of this before, however it's hardly ever this cold here
Hi Ray... You are right to question their advice... it also explains why you never heard that piece of advice before. They're wrong! In the winter it is always better to fill your tank to reduce the potential for condensation forming inside your gas tank. The condensation that forms can lead to frozen fuel lines among other problems. I think they confused an old adage with the rule of thumb. That is, in the winter you should treat a half full gas tank as empty. In other words, always stop for a fill up when your tank is half empty. The reason behind this is the less interior surface area on the inside walls of the gas tank means less area for condensation to form. In other words, the lower the level of gas in your tank the more surface area for the condensation to form which leads to more water in your fuel tank. Another benefit to always keeping your tank full in the winter is less fear of running out of gas due to unexpected traffic delays... and/or being able to run the engine and stay warm until help arrives.
That said... the good news is condensation in your tank and the dreaded "fuel line freeze up" is not the problem is was years ago when gasoline was 100% pure. Todays fuels now contain at least 10% ethanol. The benefit of ethanol is it tends to mix with water so when condensation does form in your tank... the ethanol will carry the moisture to the engine and allow it to be burnt off.
Modified by Elton Noway at 11:42 PM 1/7/2010