We cut open 23 more filters!  See what’s inside…



In 2010, FleetFilter cut open 20 filters so everyone could see the differences between the brands.  We didn’t do it for a sales pitch or show that one filter was better than another – we just did it because most people don’t know much about the insides of filters, and we thought we could show you so you can learn and make educated filter choices.  We have certainly learned a lot in our eleven years, so why not share?

But the data has gone stale, new filters have come out, old ones have gone away.  So for 2017, we cut open 23 new filters and made a few notes for everyone to see.

In the filter business, there are few manufacturers and many distributors; therefore, a lot of filters get sold to multiple sources who rebrand it and sell it in their own box.  So you may find that many of these are similar; in fact, you may find that they are identical.  For instance, it is not uncommon for Wix to buy a filter from Donaldson and put it in a Wix box – sometimes the filter is too expensive to reproduce themselves, or sometimes the original manufacturer has a patent which must be honored.  It is also not uncommon for a large manufacturer like Wix to make a filter and multi-brand it for large customers – for example, a Wix filter might be made and rebranded as NapaGold, Carquest Premium, or MicroGard.

But first, let’s learn about the parts of a filter and what they do:

  • Sealing Gasket – makes a seal from the metal of the filter to block of the engine
  • Base Plate – gives the filter rigidity and a foundation on which to mount the filter material
  • Anti-Drainback Valve – keeps the oil from flowing backwards into the engine
    • Some are silicon; some are rubber
  • Safety By-Pass Valve – if the filter gets clogged, this allows for the oil to bypass the filter so the engine doesn’t starve of oil and seize.
  • End Cap – holds the filter material in place
    • Some are metal; some are paper
    • The media is held into place with an epoxy
  • Center Tube – holds the paper media in place
    • Some are spiraled, perforated metal; some are a plastic cage
  • Media – the actual filter to clean the fluid
    • Some are paper; some are synthetic paper
    • Some media are sprayed with a phenolic resin which acts as a water barrier
    • Some media are backed with a metal mesh against the center tube for additional strength
  • Spring – keeps the filter media and end caps pushed against the base plate
    • Some are a coil spring; some are a leaf spring
  • Canister – contains all the above parts and keep them together in a sturdy package


So we cut them open, and you can see the differences inside.  Please jump to https://www.fleetfilter.com/filter-comparisons.html and check out the filters.

We only sell the NapaGold by Wix, Fram, Luberfiner, and Baldwin, but you’ll be able to see a slice of the current market for filters and what qualities they bring to the filter world.

Thank you for being a customer of FleetFilter.  Enjoy!