Should I keep fuel stored in my tank when my car isn’t in use?

Date:9 July 2013 Tags:,

A filling question

Q: For about half the year, my wife and I travel the country in our motorhome. We leave our new Mercedes E-Class parked in the garage at home. My question is, should I store it with a full tank, or can I get away with not leaving a tank of liquid gold?

A: You should do one of two things. Your E-Class probably has a plastic fuel tank, which cannot rust, so it’s possible to store the car with a nearly empty tank as long as you add fuel stabiliser and fill up with fresh fuel as soon as you start driving again. Another option is to store vehicles with a full tank of fuel and an appropriate amount of fuel stabiliser added.

The reason for this approach: to reduce the airspace in the vessel, and over the autumn and spring seasons the wild swings in daily temperature invite condensation to gather on the walls. This can lead to water in the tank, and if you have a steel fuel tank, that spells eventual corrosion. Things are worse if you’re in a region that uses ethanol in the fuel mix, because ethanol attracts and bonds with water. If your car has a plastic tank you don’t have to worry about corrosion, and you can store it partially full with stabiliser, but fill it up when you hit the road.