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
    Donaldson filter 6637

    Posted by Jesus Ramos on Oct 23rd 2020

    Great filter for my 7.3 2002 F250

  • 5
    Great filter

    Posted by Joe on Oct 5th 2020

    Installed on a '99 7.3
    This filter definitely SOUNDS like it flows more than the regular white Donaldson. I buy these from now on. Turbo wheel is still squeaky clean and haven't had an issue

  • 5
    sweet deal on a new air filter

    Posted by Kaiah McLaughlin on Sep 24th 2020

    Yeah buddy, just to clarify the filter sold at napa is not even remotely close to the quality of the Donaldson that you get from riffr-aff. And you can get the pre-filter and air filter delivered for less than the nappy dugout by itself and shipping was over $15 for me. And it was on my doorstep 2 days from the time I placed my order. My main driver (03-7.3l built to the hilt) is now going to be getting all its needs filled by riff raff!!. Thanks guys for you and your services, warms my heart knowing there are good people still in the area I was born and raised. God bless and take care, I'll be back for more lickity split.

  • 5
    Perfect fit. Used on my 2001 Excursion 7.3l.

    Posted by Mark C. on Aug 26th 2020

    Replaced same. Had been on Excursion for just about 2yrs. As usual Clay is awesome.

  • 5
    Best filter

    Posted by Jonathan Shidler on Aug 22nd 2020

    Been running this filter on my 7.3 for years it moves more CFM than the regular 6637 truck runs very happy with it. I just change it out once a year.

  • 5
    Replacement filter

    Posted by Joe on Aug 10th 2020

    Works great 2nd time I've purchased this product.

  • 5
    Donaldson Blue® 6637 Filter

    Posted by Bob Potter on Jul 23rd 2020

    arrived in 2 days , surprised it did lower egts at idle and pulling hard replaced the regular 6637 with blue and impressed a little more money but worth it .

  • 5
    Just are the best!

    Posted by James Benson on Jul 16th 2020

    Donaldson Blue is just the best. My super duty runs great with the additional air that it is able to get thru the medium. And at a great price. Don't be afraid. Just do it!

  • 5
    Donaldson Blue 6637

    Posted by Patrick Peck on Jun 29th 2020

    Bought this filter to replace my dirty 6637 white filter. It seems to breathe much better . Of course the old one was dirty ... so that may be a factor. I noticed turbo sounds like it spools a bit faster. This is one of the most economical upgrades you can do to your truck . More air in makes happy turbo....