Question about used air filter

Discussion in 'General Motoring' started by Arashikage, Sep 29, 2003.

  1. Arashikage

    Arashikage Guest

    Replaced the air filter on a '78 318 2bbl recently. A $10 paper filter of
    the same type as the one replaced. Time between changes about 1
    year/5000miles.

    I put the used filter in a bucket of water with some detergent and let it
    soak for a while before flushing and drying it. My question is as follows:

    The old filter now looks clean, but has it somehow "lost its filtering
    powers" in the abovementioned process?

    I know K&N make a big deal about their filters being washable, but as far as
    I can tell, so are the cheap paper ones.
     
    Arashikage, Sep 29, 2003
    #1
  2. K&N filters are a gauze or cloth material so they will stand up to washing.
    Paper filters are just that, some have a slight wax content to trap dirt
    but no matter what when you wet paper sooner or later it falls apart.

    Unless you live in a dust bowl changing filters every 5000 miles isnt
    needed. Do it once a year unless you are putting a lot of miles on. I find
    up in the New England area that the dust from the road chemicals and sand in
    the winter collects worse than dust in the drier months. I change all my
    vehicles air filters each spring after the roads have cleared with the
    spring rains.

    --
    Mike....................................................
    "Opportunities are spawned from crisis"
    Replaced the air filter on a '78 318 2bbl recently. A $10 paper filter of
    the same type as the one replaced. Time between changes about 1
    year/5000miles.

    I put the used filter in a bucket of water with some detergent and let it
    soak for a while before flushing and drying it. My question is as follows:

    The old filter now looks clean, but has it somehow "lost its filtering
    powers" in the abovementioned process?

    I know K&N make a big deal about their filters being washable, but as far as
    I can tell, so are the cheap paper ones.
     
    Rufus T. Firefly, Sep 29, 2003
    #2
  3. Arashikage

    Arashikage Guest

    So as long as the filter isn't falling apart (it stands up against the
    pressure from a vacuum-cleaner) it's OK to re-use?
    Yeah, I know. It was done in the process of trying to get better milage.
    Turned out that the fuel gauge was the problem, low-fuel warning light came
    on with aprox. 30 ( of 74 ) liters in the tank.
     
    Arashikage, Sep 29, 2003
    #3
  4. Of course not. Air filters load-up with dirt long before they physically
    begin to break down ("fall apart").

    The rule with a proper OEM-type "paper" air filter is if you can easily
    see sunlight or the light from an incandescent household bulb through the
    filter when you hold it up to the light, it's OK. If not, replace it.

    DS
     
    Daniel J. Stern, Sep 30, 2003
    #4
  5. Arashikage

    Arashikage Guest

    Yes, but this used filter had been washed, and most of the dirt (apparantly)
    went with the water.
    You can see sunlight through it.
     
    Arashikage, Sep 30, 2003
    #5
  6. Arashikage

    RickMerrill Guest

    Sunlight? Maybe the answer to the OP's question is, can you
    see sunlight through a New Filter? - RM
     
    RickMerrill, Sep 30, 2003
    #6
  7. Throw it away. "Paper" air filters cannot successfully be washed. When
    they get wet, the "paper's" structure changes so it's no longer an
    effective or efficient filter. This is not just writing paper we're
    talking about here!

    DS
     
    Daniel J. Stern, Sep 30, 2003
    #7
  8. Arashikage

    TOM KAN PA Guest

    << Yeah, I know. It was done in the process of trying to get better milage.
    Turned out that the fuel gauge was the problem, low-fuel warning light came on
    with aprox. 30 ( of 74 ) liters in the tank. >>
    ____Reply Separator_____
    Huh? What does the low-fuel light coming on have to do with gas mileage? Fill
    up the tank, divide the gallons to fill up into the miles put on the vehicle
    since the last fill up.
    It doesn't matter if lights come on, bells ring, whistles blow.
    They have no effect on miles per gallon.
     
    TOM KAN PA, Oct 2, 2003
    #8
  9. Arashikage

    Arashikage Guest

    Yeah, I know. I *thought* I had poor milage beacuse of the warning light.
    The air filter seemed rather dirty so I just replaced it without checking
    the actual milage like you describe.
    I could buy around 10 air filters for what a tank of gas costs here in
    Norway.
    I ended up with 0,137 liters per km on mixed highway and city driving, which
    I found acceptable for a '78 lebaron.
     
    Arashikage, Oct 3, 2003
    #9
  10. Arashikage

    TOM KAN PA Guest

    << I ended up with 0,137 liters per km on mixed highway and city driving, which
    I found acceptable for a '78 lebaron. >>
    ____Reply Separator_____
    What engine?

    I figure that's about 17.4 mpg. That sounds acceptable to me.
     
    TOM KAN PA, Oct 3, 2003
    #10
  11. Arashikage

    Arashikage Guest

    318 2bbl.
     
    Arashikage, Oct 4, 2003
    #11
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