Donaldson Blue® 6637 Filter

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(You save $13.39 )

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
    Excellent Product

    Posted by James on Dec 6th 2019

    Excellent Price

  • 5
    New Air Filter

    Posted by David Smith on Dec 2nd 2019

    Great quality filter. My truck loves it.

  • 5
    Air filter

    Posted by Wayne Neece on Nov 7th 2019

    Just what I wanted

  • 5
    Donaldson Blue

    Posted by Max on Oct 2nd 2019

    Great Filter! Great Price! Riffraff is the Best
    for OBO Powerstroke products!

  • 5
    Donaldson blue filter Wow

    Posted by Mark j on Aug 22nd 2019

    This filter made a huge difference in performance compared to KN filter, plus the cover adds another layer of motor security. Highly recommend this product, You will not no disappointed.

  • 5
    Awesome filter

    Posted by Josh Mckee on Jul 22nd 2019

    This is a awesome filter love it

  • 5
    Great product

    Posted by Scott on Jun 26th 2019

    Gave my Excursion the extra power I needed, better flow, sound, and maintaining speed when hauling I needed!!!

  • 5
    Excellent air filter

    Posted by Tim Plummer on Jun 1st 2019

    Replaced my K&N filter with the Donaldson filter due to many comments about engine performance improvement. Hard acceleration while passing was a dramatic difference. It felt effortless and smooth. Not bad for a 2000 7.3L dually! I’m sold!

  • 5
    Great filter

    Posted by Ross on Apr 23rd 2019

    Changed my filter from the original Donaldson, and am extremely happy. Will be sticking with this one from now on!