The number one problem older petrol tanks face over lay up periods is caused by the ethanol present in modern fuels. When ethanol mixes with water, most commonly as moisture in the air, the ethanol is taken from the fuel, with the water, down to the bottom of the tank. Then come spring, the water and ethanol mix is fed into carburettors and won’t ignite, and leaves unignited sludge behind to cause further corrosion.The easiest and least invasive thing you can do – chemically – is fill the tank over winter. This minimises the surfaces available for condensation to form. If you get the chance to exercise the car by letting it warm up on a dry drive once every couple of weeks, this will also help.If this isn’t possible, you could use one of our fuel additives designed specifically to prolong the life of fuel. This is a cost effective way to make sure the fuel is in the best condition come the first start in the spring.If you can’t have any ethanol in your fuel tank at all, perhaps because it’s made of fibre glass, then the only thing really suitable is to use storage fuel available from our Gulf Fuels range.This has no ethanol in it, and burns very cleanly when in use.