mzeiya
Elder Lister
In older vehicles, manufactured before the '90s, fuel tanks were made primarily of metal and tended to rust over time and this could cause a problem if the fuel pump sucked up any sediment within the fuel tank and sent it to the engine.
In addition, the rusty sediment could also plug fuel lines, as well as the fuel filter & could damage the engine itself. Luckily newer fuel tanks are made of high-density plastic, negating the formation of rust but it doesn't mean that sediment can't still get in your fuel tank.
...so what fuel level is the best to work with? At least a quarter full at all times.
why?
Because tiny particles that find their way into the gas tank settle at the bottom and they tend to stay there until your car is trying to grab every last bit of fuel it can.
Also..
In some cars, the fuel pump is located in the tank & the gas acts like insulation & lubricant as it flows around the pump. so constantly running your fuel tank dry, the fuel pump could be overheating, which will cause it to wear out prematurely.
How far can you go when the gauge hits E depends on your car. Different vehicles are configured in different ways, though most will illuminate the light when there are about 7.5 - 11 ltrs left.
so break the habit! The "I know my car" may make you sound like a bad ass but you might be hurting your engine block and other components so drive efficiently(a thing subru guys will NEVER do esp when a MK6/7 does a polite nyamaring) & fuel at credible stations!