Listen to your father's old advice about driving with the fuel tank empty - it's advice that might prolong the life of your Mercury fuel pump. The fuel in the fuel tank is needed to cool the entire fuel/combustion system. When the Mercury fuel pump is activated by the key turning in the ignition switch, the fuel enters the pump and goes straight through the pump motor, which lubricates and cools the pump motor. From there, the fuel goes on to be pressurized, a necessary step for most electronic fuel injection systems. The fuel pump's job is to maintain the proper volume and pressure levels needed to push the fuel through the combustion system. When the motor of the fuel pump begins to suffer from heat stress, the entire fuel system will suffer from weakness. In addition, consult your Mercury owner's manual about how frequently you should change your fuel filter - and follow the advice. The fuel filter protects your fuel pump from the gunk that collects in the fuel system and then finally clogs it until the fuel pump fails. Eventually, the Mercury fuel pump will fail sometime after 100,000 miles are reached on your vehicle. At that point, order a new fuel pump set from our site and install it yourself.