I am not an oil filter specialist. I am not selling oil filters. I don't have the facilities to test oil filters per SAE methods. I am just an ordinary consumer who wants to determine the best filter to use on the various Ford products owned by the members of my family and myself. There are many alternatives to the standard Motorcraft FL-820S Oil Filter available. Using the resources available to me, I am trying to determine if there is a good reason to pick one of the alternatives.

Cutting oil filters apart is probably not the best or most scientific method for comparing oil filters, but it is something I can do with the resources available to me. I plan to compare as many FL-820S equivalents as possible.

The information presented here is my opinion. If the test methods don't meet your standards, I understand. Feel free to complain. I'd love to hear suggestions on how to better evaluate the various filters. Some suppliers readily provide information useful to picking a filter (Champion Labs  freely provides information). Other suppliers seem reluctant to tell you anything (AC Delco is very closed mouth). Most suppliers fall between the extremes. Unfortunately, the most import information, the filter efficiency and filter capacity, is either not available, or not presented in a consistent manner. I don't have a way to measure these values. Even when a manufacturer provides filter efficiency information, they usually don't provide everything you need to know (quoting a 98% efficiency without reporting the applicable micron rating is not particularly useful). Most of the specification quoted in ads or on the filter carton seem to have been "filtered" to remove the most important content. Everyone likes to compare their filter to the "leading national brand." I am guessing the "leading national brand" is the bottom quality Fram filter, but this is never explicitly stated. But even Fram compares their more expensive filters to their bottom quality filter, so I suppose the Fram PH2 is fair game for comparisons. And usually, when manufacturers make statements about their filter (comparing it to the leading national brand), they are not actually comparing their FL-820S equivalent to a Fram PH2 (or whatever). They are comparing another filter they make to a different Fram filter. I think most comparisons are between FL-1A equivalents and Fram PH-8A Fitlers.

Remember - almost all filter manufacturers claim to meet the vehicle manufacturers specifications. I wish I had a copy of those specifications. It seems hard to believe that they could all meet the same specs and still be so different.

What makes for a good filter for your Ford?

• Filter media material. Most companies use either plain cellulose (i.e., paper), or cellulose reinforced with synthetic fibers (whatever they are). The media is designed to trap particles of a certain size or larger. Ford rates the FL-820S Filter at 20 microns. Others rate their equivalent at as small as 10 microns. If the filter traps very small particles, it is possible that it will load up very quickly and go into bypass mode before it is changed, effectively giving you no filter at all. Assuming your filter has enough capacity, the smaller the micron rating the better, at least as far as maximizing engine life is concerned. I would not consider a filter with a micron rating greater than 20 microns. Smaller micron ratings may reduce the filters flow rate.
• Surface area of media. More is better, as far as flow capacity and contaminant holding capacity are concerned.
• Thickness of media. A thicker media is likely to be more efficient at removing contaminants (for a given media material), and be able to hold more contaminants. However, a thicker media is also likely to provide more resistance and reduce the flow through a given area of media. Very thin media might be easily damaged.
• Filter media retainer. I call this the filter element assembly. All but the cheapest filters use metal end caps and have the filter media "potted" into the end caps. All but the cheapest filters include an inner support (filter core) made of perforated metal to keep the filter media from collapsing. The cheaper filters sometimes use paper or fabric end caps and plastic moldings for the inner support. I prefer the filter media potted into metal end caps and the perforated metal inner support.
• Filter element retainer. Filters include either a leaf spring or coil spring between the filter element and the top of the can. This is used to hold the filter parts tightly to the base. Either solution is acceptable to me.
• Anti-drain back valve. Ford modular engines need a good anti-drain back valve (ADBV). If the anti-drain back valve does not function properly, oil will drain out of the engine when it is off, and it will take a few moments for the oil to begin to flow to the chain tensioners and overhead lifters when it is restarted. This can at result in the annoying clatter of the camshaft drive chains and, possibly, excessive wear. The Motorcraft filters use a silicone anti-drain back valve. The silicone valves are more resistant to age hardening than the nitrile (rubber) valves used in some cheap filters.
• Bypass (pressure relief) valve. Ford prefers to have the bypass valve at the base end of the filter. Many filter manufacturers prefer to place it at the dome end. The dome end location is cheaper and easier to manufacture. However, for filters with dome end bypass valves, if the filter goes into bypass mode, the oil will circulate past the dirty side of the filter before passing through the bypass valve, and back into the engine. I believe that this may result in the oil picking up additional contaminants and returning them to engine (besides not having been filtered at all).  I prefer base end bypass valves. It is also important to have a bypass valve that opens at the correct pressure differential.
• Filter can. You need a strong filter can to prevent ballooning of the filter. Some manufacturer's include an anti-slip coating on the can. Others include flats or flutes so you can use a cap end wrench. And at least one includes a hex nut on the cap, so you can use a standard wrench or socket. I usually install filters by hand, and use either a cap wrench or strap wrench to remove them. Having a feature on the end so you can use a cap wrench or a standard wrench is an advantage for some Ford models where the filter is in a confined space that makes it difficult to use a strap wrench.
• Base. The base needs to be strong and have the proper threads (M22-1.5 for Fords that use the FL-820S). I feel you should have at least 3 full threads.
• Base gasket. The gasket needs to be of the proper size. I prefer gaskets that are tightly bonded to the filter base. In the past I have had gaskets stick to the filter adapter on the engine. In some cases, the adapter is not easy to see or reach. Leaving an extra gasket behind is a good way to get a leak. Some of the premium filters include lubricated gaskets (Teflon, or graphite). This is a nice feature since it makes the filter easier to remove.