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Riffraff Diesel Performance Inc, Engines - Supplies, Equipment & Parts, Eagle Point, OR


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Donaldson Blue® 6637 Filter

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Part Number:

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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Product Reviews

Showing reviews 1-10 of 53 | Next

  1. Best Filter For Your 7.3 5 Star Review

    Posted by on Aug 10th 2018

    I previously bought an $$ S&B filter kit with the big intake box. The replacement filters were expensive and the big box really made accessing the powersteering reservoir a real pain. Pulled that out and replaced it w a battery tray and this Donaldson filter. Superior filter at a better price and now lots of room under the hood without that plastic intake box. Riff Raff is the place to buy from a great prices and fast shipping and excellent customer service.

  2. Blue 6637 5 Star Review

    Posted by on Aug 7th 2018

    Nice filter for the price.

  3. Best 6637 filter diy intake 5 Star Review

    Posted by on Jul 30th 2018

    I am a fan ... Feel the squeal...no mpg gain but I believe it lasts longer and cleans the air better. I only buy the blue and only riffraff sells it.

  4. Great in dusty conditions 5 Star Review

    Posted by on Jun 30th 2018

    The filter last a long time in dusty arizona conditions, and wont pass abrasives like some other oiled filters.

  5. Does the job better 5 Star Review

    Posted by on Jun 26th 2018

    Replaced a standard 6637 with this hi flow filter. Looks as good as it performs.

  6. Donaldson blue 5 Star Review

    Posted by on Jun 6th 2018

    Just what I needed and expected.... Quality and it can breathe now

  7. Great Filter 5 Star Review

    Posted by on Jun 2nd 2018

    Perfect fit. Well made. Water proof. What more could you want?

  8. Best filter I've used 5 Star Review

    Posted by on May 30th 2018

    Huge improvement over the OEM air box! Pulls much harder and sounds great! I'll never use a paper element filter again.

  9. Filter 5 Star Review

    Posted by on May 7th 2018

    Doesn't seem to really be any different than any other filter but it keeps the air clean and my turbo happy so I'm good!

  10. Great filter 5 Star Review

    Posted by on Apr 19th 2018

    Great filter! RiffRaff is great as well!

Showing reviews 1-10 of 53 | Next