Oil Filters: Filtration Media and Types Explained

Oil filters protects the engine from contaminants. These various impurities can cause major damage to the engine and surrounding parts. That’s why it’s essential that integral engine parts like the valve-train and connecting rods, as well as the camshafts are protected and lubricated. Finding the ideal oil and pairing it with an effective filter can definitely prolong the life of your engine.

Still, if you decide to try out oil filters, there are some things you should know. First, let’s quickly look at everything the motor oil has to do:

  • Lubricate internal parts
  • Suspend wear particles
  • Transfer heat so that it reduces the temperature of the engine
  • Absorb contaminants
  • Seal the piston ring

Oil Filter Media


Typically for low-cost oil filters; cleans up to 40% of the motor oil and is usually replaced every 3000 miles.


A more stable option that cleans up to 50% of the motor oil. You should check or replace it after 5000-7000 miles.


More expensive than cellulose. Micro glass mesh is much finer than cellulose or synthetic filter media and can last from 2 to 5 years, or 10000 miles.

Types of Oil Filters

Unfortunately, not every oil filter is compatible with your car. In fact, manufacturers actually dictate the compatibility of your engine with different types of oil filters.

Primary oil Filters

Also known as "full-flow filters" because 100% of the motor oil passes through the filter under normal operation. These filters have lower flow restrictions and allow the passage of smaller contaminants. In cold weather, motor oil will thicken and the filter must operate without introducing fluid flow restrictions.

As a result, they feature a bypass valve in case the filter becomes clogged. At specific pressures the valve will redirect the oil around the filter and to the engine. In this scenario it's best to have motor oil flowing to the engine than none at all.

Secondary Filters

Secondary oil filters or "bypass filters" work independently of primary filters and only work on about 1-10% of the motor oil. They have nothing to do with the bypass valves mentioned above. These filters can be added to most engines because they plumb into fittings on the engine block. They can also be mounted remotely.

Conventional oil filters filter out smaller contaminants with a cellulose membrane. They are a secondary type of filter that needs to be replaced more often.

Spinner Filters

Also known as "centrifugal," these oil filters have to spin the oil around in order to trap motor oil contaminants. These filters are comprised of two sections — a housing chamber and a membrane. The centrifuge is powered by the vehicle's compressed air system which revolves around a bearing.

As it spins the contaminants are thrown onto the filter media. The base gasket is one of the most important parts of this particular filter. It’s not very durable, but it prevents the motor oil from leaking, which is a crucial function. As such, if you have one of these oil filters, be sure to check your base gasket with a mechanic every three months.

Thermal Chamber Filters

Thermal chamber oil filters work in two ways. First, they filter the motor oil to remove contaminants. Second, they refine the oil by heating it to boil off additional contaminants. In order for this process to work the vehicle uses electricity which reduces fuel efficiency.

Magnetic Filters

Magnetic filters are used to eliminate metallic contaminants. These filters don't need to be replaced and simply cleaning them should suffice.

Final Thoughts

In the end, picking which oil and filter to use really comes down to application and budget. An old beater isn't going to need top of the line motor oil and a premium filter. On the same token, a prized sports car shouldn't use the cheapest oil and filter you can find.


Richard Reed
I've been a General Manager of a moving company and I've also been a Professional Mover for over 30 years. I've driven flat beds, reefers, dropdecks, moving vans, heavy machinery, etc. In my time as a Mover I've driven over 1,000,000 safe miles. My days of moving and driving truck are past me but The Vehicle Lab allows me to share the knowledge I've gained over the past 40 years.
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