Oil is the lifeblood of the engine of your car or truck (or motorcycle, boat, plane, tractor or others). Quite simply. But as the oil circulates through the engine, it also drains a number of contaminants (to put it simply, dirt). This dirt can obviously damage your engine. Until causing an irreparable failure.

How do oil filters work?

The first internal combustion engines did not use oil filters and with the poor quality of oil available at the time, vehicles needed frequent oil changes. Finally, the first full circulation oil filtration system was developed. This device allowed oil to flow through the filter before reaching critical components inside the engine. 

So far everything has been fine, but there was (and still is) a big caveat: The vast majority of pressurized lubrication systems inside internal combustion engines include some form of filter deflection to protect the engine against the lack under certain circumstances. A good example is the very cold weather. In this situation, if the oil is too thick, it can bypass the filter. Oil can also bypass the filter when the filter is clogged. In these cases, the best oil for 6.0 powerstroke is sometimes not filtered, even when the engine is equipped with a full circulation oil filter. 

In operation, the oil enters the filter through a series of small holes on the outer edge of the base flange. The oil is then directed into the filter, to exit into the engine through the large hole in the center. Most modern oil filters are equipped with an anti-backflow valve. This is often a form of rubber membrane that covers the perimeter holes on the base flange. The diaphragm experiences pressure from the sides as the oil enters the filter housing. When the engine is not on, the rubber membrane covers the holes. Obviously, the anti-backflow valves keep the oil in the filter. They also prevent dry engine starts (when the engine starts without oil).

Early oil filter designs

Early oil filter designs relied on a replaceable element inserted into a metal housing. To change the filter, you had to remove the housing, discard the element, clean the housing, add a new filter, and reinstall the assembly in the engine. In the middle of the 20th century, screw-on filters gained popularity. The filter element and the cartridge are self-contained. Just remove the assembly, throw it away and screw in a new filter when draining. Today we are witnessing a return to the first oil filter design. In this system, the oil is filtered by an element contained in a separate housing, as the replaceable filter element is more environmentally friendly than a screw-on filter. Remember that today’s motor vehicles require much less oil change than those of the past.

Types of oil filters today

There are many types of oil filters available today, and there are an equally large number of tests in which various filters are taken apart and diagnosed. The truth is, not all oil filters are created equal. Result: Quality is generally proportional to price.

But are there any real differences between standard filters, high performance filters, racing filters and synthetic filters? Absolutely.

First you need to consider the mission of the motor vehicle. The perfect illustration is a racing car. This will rarely, if ever, experience cold starts (usually the oil is heated before starting). The oil is often changed, simply because the engines are inspected and regularly disassembled. The oil in racing car engines was once thicker than that found in passenger vehicles, but today it is the other way around. Runners have discovered the benefits of a light oil. 
Without going into detail, it’s not uncommon to find racing engines filled with oil as light as zero grade. Racing filters are designed to work with these oils. Some racing filters are not equipped with backflow preventers.

On the flip side, many racing oil filters have an internal holder that withstands high temperatures and water-in-oil levels that can clog standard types of oil filter holders. Many racing oil filters are designed to provide high levels of oil circulation with lower restriction. Some racing oil filters designed for use in endurance applications (eg, 12 or 24 hour races) contain a different media designed to trap smaller contaminants.

Some racing or high performance filters are made with sturdier housings to protect against track debris. Heavier bases are also built into some of these filters. This is to ensure that the filter body does not flex under high pressure conditions. Some are made so that they are tied to prevent accidental loosening. Some high performance filters also incorporate rolled wires rather than chopped wires to ensure the filter does not come apart during installation.

Paper or plastic?

Another difference is the filter media. Some filters are equipped with a synthetic filter media (rather than a pleated paper backing). Synthetic support is considered to be able to trap small contaminants for longer (more kilometers). In addition, some synthetic filters include special rubber blends for sealing rings and pressure valves. The goal? Just like the filter media, they are designed to last longer. Finally, some synthetic filters have larger bodies (usually longer) than conventional filters, which means they have a higher capacity. Due to these factors, some synthetic oil filters have a lifespan of 11,265 to 40,233 kilometers.

As you can see, there are plenty of variables inside the oil filters. So what is right for your car, truck, motorcycle or other vehicle with internal combustion engine? The answer is: it depends. You should carefully study the specifications of each filter to determine the right one for your particular application. If your vehicle is newer, you should also seriously consider the warranty. Some filters may be considered incompatible by the car manufacturer and this is important when it comes to warranty claims.

In fact, you have to think twice before using a high grade synthetic oil and high performance oil filter in an old jalopy. And similarly, it doesn’t make much sense to use the cheapest oil and filter possible in a vintage Ferrari. Finally, choosing a filter is like choosing an oil. Take the one that best fits the application and your budget.

Some facts about filtration

  • The oil filter required for a six-cylinder Buick is very different from that found in a 7,000 horsepower (or more) Top Fuel dragster. In both cases, the mission is the same: to keep the oil clean.
  • Filters are not all created equal. The intended application for a given oil filter has a great impact on the component design. The oil filter in a racing car is very different from the filter in a passenger vehicle.
  • In a typical passenger vehicle engine, the oil enters the filter at the filter pad, usually built into the engine block. From there it circulates through a series of small holes on the outer perimeter of the filter. At this point, the oil is forced to pass through the filter element (from the outside to the inside) and then to the center of the filter (back into the engine through a large threaded hole under the pointer).
  • When a filter works well, internal engine components, such as connecting rods, camshaft, and timing, are protected from contaminants that can cause major damage. These components are expensive. Choosing the right oil and the right filter can definitely promote long life.