Donaldson Blue® 6637 Filter

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(You save $14.39 )

Donaldson Blue® 6637 Intake Filter for Ford 7.3L 94-03

Donaldson Blue® air filters with Ultra-Web® nanofiber technology protect engines by providing better initial and overall efficiency compared to conventional cellulose media. Donaldson invented air filters for heavy-duty diesel engines over 100 years ago and were the first to develop nanofiber air filter media for the diesel engines, with more than 20 years of proven performance. 

  • Longer Engine Life - Donaldson Blue™ air filters provided better engine protection by allowing much less contaminant to pass through than cellulose air filters but still maintaing a higher flow rate
  • Longer Filter Life - Smaller interfiber spaces of Ultra-Web® nanofiber technology hold more submicron contaminant than conventional filters with cellulose media, delivering longer filter life
  • Increased Flow - Utilizing the nanofiber Ultra-Web® media has allowed for a 37% increase in flow over the standard 6637 cellulose filter. It has also been tested to flow over 1300 CFM+.
Media Type
  • Ultra-Web® Nanofiber Technology -- Exclusively in Donaldson Blue air filters
    • Engineered to perform in extreme temperature and humidity conditions, unlike ordinary nanofibers and cellulose which aren't hydrophobic
    • Proven in the real world – used in diesel engines for nearly two decades
    • On-road applications are guaranteed to go twice the distance compared to standard cellulose filters

We suggest buying them in quantities of 2 as your shipping won't increase much and you will save money.

100% Made In The USA


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  • 5
    Donaldson blue 6637 filter

    Posted by Jack C on May 19th 2021

    I can’t believe you could have made it better, but you did. It’s only the Donaldson blue for my truck.

  • 5
    Awesome Filter

    Posted by Hunter on Apr 15th 2021

    Best filter around in my opinion especially with the filter cover I run it on all my trucks

  • 4
    6637 filter

    Posted by Rickey on Apr 7th 2021

    Good improvement over factory

  • 5
    Air Filter

    Posted by Dicky Murph on Mar 25th 2021

    Works very well, definitely opens the truck up a bit and gives you some more low end power. Would recommend if you have an early 99 7.3 to just buy the whole filter kit, nobody seems to have or be able to get the 4in pipe bent at a 45 degree angle to fit the truck.

  • 5
    Good value

    Posted by Geno on Mar 11th 2021

    Lasts quite a while

  • 5
    this filter sounds like it flows well,

    Posted by Jason Schrader on Feb 8th 2021

    best price i could find

  • 5
    Great Filter

    Posted by Grant Mott on Jan 3rd 2021

    Swapped to this from a Napa wix and I am really impressed. Almost all smoke on acceleration is gone, and I seem to be able to spool up quicker.

  • 5

    Posted by Dave J on Jan 2nd 2021

    Replaced the old DuraLite on my 97. Super nice filter and a great price.

  • 5
    Way better

    Posted by Unknown on Dec 17th 2020

    Really opened up my truck and let that Garret turbo scream!