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 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!

  • 5
    Love it

    Posted by James on Mar 31st 2019


  • 5
    Donaldson Blue 6637 Filter

    Posted by Walt H. on Mar 26th 2019

    If you need a open air filter...this is the one.

  • 5

    Posted by Joe St Antoine on Mar 18th 2019

    Great product. Highly recommended.

  • 5

    Posted by Luke on Feb 19th 2019

    So much better flow than my Wix filter. No wonder Donaldson is the king of filtration. I can't believe the difference from just changing the filter on my Tymar setup. Thumps Up on this!

  • 5
    6637 blue

    Posted by Dave on Jan 22nd 2019

    Moved from desert southwest to the Carolinas, needed a filter that is resistant to the moisture. Works great and should be more durable than standard 6637.

  • 5
    Donaldson blue 6637

    Posted by Unknown on Jan 2nd 2019

    Happy with these filters, I purchased 3 this time around.

  • 5
    Great filter

    Posted by gotgarkala on Dec 26th 2018

    I had the AFE stage 2 set up, but after reading about how poorly the washable, oiled filters actually filter, I decided to get away from them.
    If you've got the stock set up, installation will be easy. I didn't, so I had to cut big chunks of the AFE battery box and get a 45 degree 4" pipe to get her in.
    Seems to get ass much air in as the AFE. And the water repelling quality gives me piece of mind.
    Great product and fast shipping.