Donaldson Blue® 6637 Filter

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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

NOTE: This filter is disposable and is NOT washable. 

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  • 5
    Air filter

    Posted by John Davis on Jun 10th 2024

    Great filters! I love buying stuff from Riffraff always fast shipping, fair prices and quality merchandise .

  • 5
    97 7.3

    Posted by Antoine on Feb 16th 2024

    Love the filter, so big it fits just right. 200 miles on it so far and way more air flow. I don’t have box or heat shield and can tell the difference. I will go with this product until proven otherwise.

  • 5

    Posted by JAY on Feb 1st 2024

    Love it. Wish it came in Red

  • 4
    Good filter

    Posted by Unknown on Nov 16th 2023

    Good filter

  • 5
    Great filter

    Posted by Jason M. on Nov 14th 2023

    The last blue filter lasted 15k miles in a mix of dusty farm and construction site work, and highway use. After blowing it out twice with air, pleats were getting filled with fines. No indication of dusting in the intake system. Happy enough to buy two more.

  • 5
    Donaldson 6637

    Posted by Sz on Oct 27th 2023

    Flows better than a napa 6637

  • 5
    Donaldson blue air filter

    Posted by Gary on May 22nd 2023

    Mounted this air filter on a 94 dodge 5.9 12 valve Cummins, absolutely came alive with this air cleaner, way more air flow, motor can breath. Was a night and day difference from the another aftermarket air cleaner I had on it.

  • 5
    Blue filter

    Posted by Victor on Apr 15th 2023

    Was initially concerned, the base where the clamp goes felt very stiff. Was concerned the clamp wouldn’t be able to squeeze hard enough to seal. But it works well. The rubber is not to hard. The hole filter is of good quality.

  • 4
    Nice filter

    Posted by Ty Osburn on Mar 11th 2023

    Fast shipping, decent price. Will have to wait and see how it performs over time. So far seems to work well.