What's the best way to keep your fuel pump well maintained?

- Apr 26, 2020-

Actually, much of what you read about fuel pumps doesn’t apply to most newer cars. First is the old tale about not letting your fuel tank get low. I’m not sure how many people who talk about this have ever removed a fuel tank and looked at how the fuel pump is mounted in the fuel pump capsule. In most cases it is not at the bottom of the capsule but rather about 2 to 4 inches from the top of the capsule.

So depending on the depth of the tank the fuel pump might not be surrounded by fuel at three quarters to one half tank. Point is, it is not fuel surrounding the pump that does the cooling, it is the fuel flowing through the pump and as long as the engine is running there is fuel flowing through the pump.

This also ties in with picking up dirt from the bottom of the tank if you let your fuel level get low. Another fantasy because the fuel pickup tube inside the tank does not move up and down, it is positioned at the very bottom of the tank and is always picking up fuel from the bottom of the tank, whether the tank is full or almost dry.

Next is fuel filters. Although it is a very good idea to routinely change the fuel filter on older cars, on modern cars most fuel filters are inside the fuel tank and are part of the fuel pump capsule. This makes them highly cost prohibitive to replace routinely as you would have to drain the fuel tank, remove the fuel tank and replace the fuel pump capsule assembly (with the new filter). This could cost upwards of $500 so most modern fuel filters are changed with the fuel pump when it fails.

So what can be done to prolong the life of your fuel pump? Basically only a couple of things. First is to keep the fuel tank free of water. Water forms in fuel tanks from moisture in the air entering the fuel tank. The moisture laden air (especially in the summer) enters the tank to replace the fuel leaving the tank. Once inside the tank the moisture from the air condenses into water and goes to the bottom of the tank where it sits until you remove it.

You remove the water by adding a container of isopropyl dry gas / gas line anti-freeze / etc. (lot of names for it) once every month. This will blend with the water and cause the water, isopropyl and gas to mix through agitation as the car moves. Once blended together the mix of alcohol, water and gas is pumped up to the engine and harmlessly burned.

Just make sure you use an isopropyl product not methanol as methanol will keep the water from freezing in cold climates but it will not facilitate the mixing of the three products like isopropyl does and therefore the water stays in the tank.

Finally, is being careful about zapping the pump with high voltage. This happens when you have a dead battery and call for a tow service to jump start your car (never a good idea but sometimes necessary). Once the booster cables are connected the tow driver may push a switch that ups the voltage being applied to your car’s electrical system to make it start easier. This surge of voltage can and often does damage the windings inside the fuel pump motor.