How a fuel filter works

Today I changed my fuel filter in my Suburban. As I am wont to do, I cut the thing open to see how it worked. I thought I would share with you what I found out.

First, let me explain and apologize. There used to be a fiber/paper filter connected to some of these metal pieces. Particularly the black burned parts. That is where the apology comes in. I had so muchFull filter shot. Input to the left, output to the right. fun cutting the filter apart and thinking about how it has spent its whole life holding gasoline, that I just knew it would make a neat fire. So my son and I stood back and threw a flame at it. Boy was it fun. The result though is that you don’t really get to see it in all its glory. Sorry.

The first picture is the filter just cut in half. When I got it open I had cut through a paper filter that was connected at the right side (the output), but not the left side (the input). And this connection/disconnection is what makes the filter do its work.Input for the fuel filter.

The second picture shows the left side where the fuel comes in from the fuel tank. The little disk would be inside the can and connected to the paper filter, but not to the can. Fuel would pour into the can (through the threaded hole on top) and splash around that disk forcing all the fuel on the outside of the fiber filter (but still inside the can).

In picture three you see where the bottom of the paper filter is connected to the output hole. Gas cannot go out that hole without passing through the filter. Therein lies the mechanics and simplicity of this device.

Output of fuel filter to the engine.Again, fuel passes in and is forced to the outside of the paper (or maybe a fiber of some kind) filter. But to leave the can and continue to the engine of the car, it must be sucked through the filter on its way out.

How do you know if you need to change the filter? In México you can just change it every 6 months and you are probably good. I am not sure what the normal recommendation is. If you blow into a new filter, you should be able to blow without much resistance. As the filter does its job and starts to collect gunk from your fuel, then trying to blow through it will provide quite a bit of resistance. The first time I changed my filter here I could hardly blow through it at all. I am surprised that gas even got through.

Does anyone know what the filter is made out of? Is it a paper material? Fiber of some kind? (I can Google, but I am trying to get you to comment).

You can click on any of the pictures to get a bigger version.

5 thoughts on “How a fuel filter works”

  1. She had to tell me often not to play with fire. I heard her. I just did not always listen.

    Now is probably not the time to talk about the time we had fun with the gun powder.

  2. YEs, out here in the middle of the Canadian Rockies, when the car stumbles down the highway, dying while I’m restarting it several times in neutral next to high speed traffic, you know you got one of 100 problems. I mean all those ‘rigid with age’ little connecting tubes around the carb of this 86 Olds Calais and now loose coupling that a past enterprising unknown mechanic has installed, it’s a wonder I have pressure doing anything. Replaced the oxygen sensor from another similar car and it didn’t not make it work. I did install two ring magnets out of an old microwave and haven’t evaluated it yet cause of this slowed down motor. i also magnetize honey for medicinal purposes.
    Thanks for the easy blow though confirmation I Googled for. Keep up the uninhibited photos. Mensmaximus Rules!

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