Rick's Free Auto Repair Advice

Oil filter quality studies

Oil filter studies and Fram

The online oil filter studies say that Fram is an inferior product. But the “studies” are a joke because the tests performed are irrelevant to oi filtration efficiency.

UPDATE: As you read this rebuttal to the oil filter study, keep in mind that Fram was sold to Honeywell and then sold again to UCI-FRAM AutoBrands and is now owned by First Brands Group. First Brands owns Anco and Trico wiper blades, Centric and Raybestos brakes Airtex fuel pumps, Carter fuel componenst, Autolite spark plugs, and Strongarm lifts.

Also keep in mind that the number of choices in filtration media have increased dramatically since the 60’s. There are now over 80 different types of filter materials, so pleat count and square inches of filtration material mean NOTHING. It’s the filtration media efficiency that counts.

Oil filter tear down studies are worthless

If you’re a motorhead you’ve probably seen the online oil filter studies where a self-proclaimed “non-lubrication expert” cuts apart oil filters to compare their construction. The studies don’t do any actual testing and contain many incorrect assumptions and projections that have little to do with oil filtration. So, let’s take a look at the study “findings.”

The number of oil filter inlet holes is irrelevant to a filter’s quality

First, the study makes a point of discussing the small oil inlet holes on FRAM filters. But if the volume of the inlet holes matches the volume of the outlet hole, that’s all that counts. So the whole point about small inlet holes is basically bogus. As long as the total volume of all the inlet holes is equal to the volume of the outlet hole, everything is A-ok. Do you really think the engineers at Fram didn’t think of that?

The Square Inch of filtration material is irrelevant. It’s the filter media efficiency that counts.

Next the studies compare the number of filter media pleats and square inch count of the media itself. A person with no filtration knowledge would read this and automatically assume that more filter media means better filtration. But the filter’s “quality” depends on the filter media’s efficiency, not the volume of filter media.

Motor oil filtration media efficiency varies

There are over 80 different types of filter media materials out there. Each one has different filtering characteristics. And that doesn’t even cover the proprietary filter media developed specifically by oil filter manufacturers. If a filter media has a larger surface area but poor efficiency, it will allow larger particles through. In that case, what good is all that surface area? I wonder why the study didn’t actually TEST the filter media to measure its filtration efficiency. Without that data, the study seems to be standing solely on a “more square inches is better theory” Until we know the efficiency of the filter media, the number of pleats and total surface area is irrelevant.

Even if we did know the dirt holding capacity of the filter media, is that all we need to know? Today’s engines are much cleaner than vintage engines. Engine computers demand precise intake air control so the engine doesn’t get un-metered air to throw off the air/fuel mixture. That’s why most late model cars have tightly enclosed air filter boxes and air filters made out of cellulose and synthetic materials. So if dirt isn’t getting into the engine from the outside, where is it coming from?

Dirt comes from blowby combustion gasses that include water and soot. And condensation that forms in the crankcase can oxidize the oil and rust metal parts. But modern oils are much better at preventing that oxidation and rust, especially if you’re using synthetic oil. What you should be concerned about more than dirt capacity is the filter media’s ability to grab onto products of oil degradation.

For example, multi-viscosity oil contain viscosity index improvers (VII). The higher the viscosity index range of the oil (10W-40, 20W-50, etc), the more high density VII the manufacturer uses. These high density VII shear more easily and sheared VII, along with high heat and acids can cause sludge. The filter must be able to capture those decomposed products and hold them. The method filter makers use is similar to the way rock candy is made. The filter fibers must be attract and hold the decomposed particles. That ability is one of the characteristics differentiates a 3,000 mile filter from a long-life 7,000 mile filter.

Of course, even if we did have efficiency ratings, the next question is, “How much surface area is enough?” There’s no good answer to that. Because even if we assume that you change your oil and filter religiously every 3,000 miles, it’s the condition of YOUR ENGINE, what kind of AIR filter YOU use and how often YOU change it (which is based on actual conditions—not mileage), what type of driving YOU do, the operation of the PCV valve* (see footnote 1), and YOUR overall engine performance (worn spark plugs and wires produce more misfires) that determines just how much junk ends up in the oil and the filter. If you really take care of your car, drive “right” and install a filter with the lowest square inches of filter media, you may actually have more than enough filtering protection. That would make the study’s assumptions irrelevant—which is my point. More on how much is enough later in the story.

The thickness of an oil filter end plate is irrelevant

The end plate is what threads onto your engine. It pulls the rubber gasket up to the mating surface. As the gasket meets the mating surface, it compresses. As long as the end plate keeps the gasket compressed, it has done its job. Extra thickness beyond what is necessary to hold the gasket against the mating surface is simply useless. Bottom line, the whole end plate discussion is bogus. The question is really, how much thickness is enough. And the answer is: It has to be thick enough to compress and hold the gasket—period. Anything thicker is a waste.

Oil filter end cap construction is a You-Get-What-You-Pay-For Issue

Now we’re talking turkey. Let’s say we have a filter material that’s very efficient and the pleats are well formed. But if the oil rides up or down towards the end caps and those end caps aren’t sealed properly, it’s all for nothing. The oil will take the path of least resistance and seep past the end caps and down the center tube. It won’t open the bypass valve. It will go between the pleats and the end cap.

The filter “studies” make a big deal out of cardboard end caps. Let’s get our terminology straight. They’re not cardboard in the traditional sense. The material is resin-impregnated cellulose. That means it’s plastic and cellulose. It’s cheap and it’s non-porous. But it also has another advantage—it glues up easily to the end of the pleats. In fact, it’s easier to glue filter media to resin impregnated cellulose than it is to glue it to metal. THAT’s why some filter companies use it.

Now here’s the bottom line, regardless of which filter manufacturer you look at, they all make cheap filters for the economy-minded consumer. And many cheap filters have resin impregnated caps because they’re cheap and they work. It’s that simple. One of the “better” manufacturers in this “study” makes a private label filter for a large retailer. Cut that puppy open and you’ll find fiber end caps glued to the pleats. Do they work? Yup. Will they last 7,000 miles? Doubtful. But they’ll probably do just fine for 3,000 miles. So it doesn’t make any sense to compare the construction of a $9 filter to a $3 filter. If you fill your crankcase with expensive synthetic oil and slap on a cheap filter, well, don’t be surprised that the filter won’t go the distance—regardless of which brand you choose. If you buy a $3 filter that HAS metal end caps, are you really getting a better product? Does the metal end cap give you any more protection against pleat separation? No proof of that in these “studies,” is there? Had the tester actually tested the filter to see when the pleats separated from the end caps, THEN you’d actually have data. But they didn’t and that’s why end cap construction, in my mind is another bogus issue.

Anti-drainback valve construction is also related to filter price.

Nitrile is cheap. Silicone costs more. Guess which material a manufacturer will use for the anti-drainback valve on a cheap filter? Do you need silicone? Maybe. If your filter is mounted sideways or at an angle on the engine, the oil in the filter will drain back into the engine at shutdown unless it’s stopped by the anti-drainback valve. An empty filter means a delay in building pressure at startup—the most critical time for an engine. So the anti-drainback valve can be very important depending on where your filter is mounted and how long you keep it in service. If your filter mounts end-plate-up, the whole anti-drain back valve issue is a moot point—oil doesn’t drain straight up. Nitrile anti-drainback valves DO harden up and lose their sealing ability as they age. So if you don’t change your oil on time AND your filter is mounted at an angle or sideways, quit being a cheapskate and buy a filter with a silicone anti-drainback valve. All cheap filters have nitrile valves. Silicone valves are either orange or grey. Just look through the oil inlet holes and check the color. Enough said?

The Story of the Lonely Bypass Valve

The bypass valve is like the Maytag repair man–it’s idle most of the time. Its job is to bypass oil past the filter media if the media is plugged.* (See footnote 2) What does it do the rest of the time? Nothing. When does the filter get plugged? When the oil is loaded with crud and degraded oil byproducts. Why is the oil loaded with crud? Because YOU don’t change your oil on time and you don’t take care of your car. If you don’t care enough to maintain your car, why do you care if the oil is bypassing the filter?

Seriously folks, this one is a no-brainer. I read the studies and I can’t find where anybody actually TESTED the bypass valves to see if they leaked. Instead the study seems to rely on a letter from a guy who says he worked for FRAM years ago. That guy says the bypass valves were molded from plastic and they weren’t formed well. The guy didn’t sign his letter because he’s afraid of being sued. Do we know if his information is real? Nope.

FRAM manufacturing plants meet ISO 14001 and ISO/QS 9000 quality certifications. Don’t know what ISO quality standards are or who ISO is? Read this:

“ISO (International Organization for Standardization) is the world’s largest developer and publisher of International Standards.

ISO is a network of the national standards institutes of 161 countries, one member per country, with a Central Secretariat in Geneva, Switzerland, that coordinates the system.

ISO is a non-governmental organization that forms a bridge between the public and private sectors. On the one hand, many of its member institutes are part of the governmental structure of their countries, or are mandated by their government. On the other hand, other members have their roots uniquely in the private sector, having been set up by national partnerships of
industry associations.

Therefore, ISO enables a consensus to be reached on solutions that meet both the requirements of business and the broader needs of society.”

For more information on ISO, go to www.iso.org

So here we have a study that was conducted by a “non-lubrication expert” who cuts filters apart in his basement but doesn’t actually perform any tests, and a letter from an obviously disgruntled former FRAM employee. On the other hand, we have an international standards organization that certifies quality at every major manufacturer. Who are we to believe? If you don’t think ISO certification is important, then perhaps you discount the fact that Champion Labs is also certified by ISO. Is their certification bogus too? Don’t get me wrong. Champion Labs makes great products and they also make really inexpensive filters under private label for large retailers. We owe them and FRAM the benefit of the doubt that they’ve tested their filters in real world conditions and the filters passed the tests in order to gain ISO certification. To me, that’s a more important indicator of quality than a study that’s biased against FRAM—a study that apparently didn’t actually perform any tests. (Feel free to correct me if I’m wrong about that point)


There is a bottom line to this.

Every filter manufacturer makes high and low end filters. Want a high end filter? Great! Spend more and buy one that’s made with synthetic glass/cellulose filter media, mesh pleat backing, a metal core tube, metal end caps, silicone anti-drainback valves, and spring operated bypass valves. Oh, and buy a filter from a manufacturer that’s ISO rated for quality.

As for an oil filter “study” that doesn’t actually test the efficiency of the filter–well, take that for what it’s worth. It’s a biased opinion piece masquerading as a “study,” sprinkled with a few irrelevant facts.

My disclaimer

I do NOT work for FRAM. They’re a major player in the automotive industry. In short, they’re no slouch outfit. I wrote this opinion piece because I didn’t think the oil filter study was nearly as objective the authors would have us believe. And, I saw lots of people quoting from it as if it were the “bible.”

Always remember this: Never believe anything you read on the Internet–not even my stuff. This is all my opinion. Don’t take it as anything more than that. Now take a deep breath and read the footnotes

1. In the old days, car makers let blow-by gases run out a tube on the back of the engine. Blow-by gasses create smog. They contain soot. In other words, they pollute. What to do with blow-by gases if you can’t eliminate them? Yeah, burn them. So car makers suck the blow-by gases out of the crankcase and into the intake manifold. Wouldn’t that create a vacuum inside the engine? Yes, except that car makers allow fresh FILTERED air in to replace the gasses that were sucked out. See where I’m going? If you don’t change your air filter or you have a leak in the air duct, you suck DIRTY air into the crankcase. If you drive in dusty conditions, you can bet you’re going to suck in more dust. Where’s the PCV in all of this? Well, the job of the Positive Crankcase Ventilation valve is to close off the route from the intake to the crankcase in the event of a backfire. But since the PCV is always sucking blow-by gases and some oil vapor, it can clog up and restrict the flow. When that happens, more crud stays in the crankcase. How do you test a PCV? Shake it. If you hear a sharp metallic sound, it’s good. If it feels mushy, chances are it’s gunked up and should be replaced. Unsure? Replace it. They’re cheap.

2 There are times when the bypass valve can open even if the filter isn’t clogged. Multi-viscosity oil is supposed to flow well at low temps. But flowing well at -20° is a relative term. There are instances where cold oil can build oil pressure inside the filter casing to the point here it forces the bypass valve open. However, once the oil heats up, the bypass valve should close because the bypass spring pressure will be greater than the resistance offered by the filter media. The real question is this: if the oil is cold and thick at startup, is it carrying contaminants that should be filtered? Maybe so, if the there’s crud on the bottom of the oil pan. But if you’ve ignored oil changes to the point where you’ve got that sludge buildup, why do you care if the bypass valve is open. Your engine will be toast soon anyways.

© 2012 Rick Muscoplat

Posted on by Rick Muscoplat

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