FRAMoil filters

FRAM is probably the most well-known filter brand, instantly recognizable, and with a reputation for balancing capabilities, features, and price. FRAM has a long history of innovation in oil filters. The trouble is, while FRAM once enjoyed a sparkling reputation, professionals now tend to shy away from its products. Researcher Russ Knize, who is otherwise a temperate and moderate reviewer, encourages consumers to boycott FRAM and calls its pricey Double Guard filter "junk." FRAM oil filters are made by Trico.

FRAM is known as a manufacturer of affordable filters that come in a wide range of quality levels. The company claims a somewhat vague 95% efficiency. The filter medium is a proprietary combination of glass fibers and cellulose, and it supports a high oil flow rate. But common complaints include a thin and irregular filter medium and inferior construction (for example, it seems as if everyone mentions the cardboard endcaps FRAM uses).


K&N oil filters

K&N Engineering got its start making motorcycle racing parts and is now primarily known as a performance oil filter manufacturer. Its specialty is heavy-duty, high-flow, high-performance filters for use in motorsports and performance vehicles, but its consumer-grade products enjoy a slightly less glowing reputation. These filters tend to rank near the top of ratings, especially those ranking performance filters or those in which cost is not a factor.

K&N doesn’t publish efficiency and filtering data. The best K&N filters are attractive, indeed. They withstand high oil pressure levels and have a higher-than-average flow rate. Users and reviewers love the one-inch nut welded to the filter casing and used to tighten the filter with a positive wrench grip. The company claims its rolled threading helps to prevent thread stripping, though it’s not clear how much of a problem that really is. K&N filters are compatible with all oil types. They tend to be on the more expensive side of the market.


AMSOIL oil filters

AMSOIL oil filters are made by Champion Laboratories, a white-label manufacturer that also produces a couple of oil filter brands of its own (Champ and Luber-finer). The company is known for producing great motor oil and expensive, high-quality filters. We must also acknowledge the small matter of the company’s reputation as something like a multi-level marketing organization. AMSOIL is a direct sales company that was a pioneer in the synthetic oil market. Its sales representatives tend to have the unrestrained positivity of true believers, which has led some to jokingly suggest that AMSOIL is a cult. As the market for synthetics has expanded in the past two decades, competitors have largely erased AMSOIL’s uniqueness, which has in turn reduced the silly comparison to a cult.

AMSOIL filters offer 99% efficiency at 20 microns and are rated to last 15,000 miles (EA15K models) to 25,000 miles (EAO filters). And, in fact, AMSOIL claims that its filters are superior in every category: better efficiency, higher flow, greater capacity, and better product construction. AMSOIL filters are made by Baldwin and tend to be quite expensive.


ACDelco oil filter

ACDelco has 100 years of experience manufacturing auto parts, and is the in-house manufacturer of oil filters for GM. Similar to Motorcraft, ACDelco doesn’t actually manufacture its oil filters, which are made by Champion Labs, which is owned by FRAM. The company makes a broad range of filters for industrial, high-performance, and standard consumer applications. Strangely enough, ACDelco also makes one of our top-ranked AA battery brands.

ACDelco filters boast an impressive 98% capture efficiency at 25-30 microns. Its oil filters are distinguished by their nylon cores, which the company claims are 1.5 times stronger than a metal core. As you would expect from a GM OEM filter maker, ACDelco filters are generally inexpensive.

Researcher Russ Knize praises the ACDelco filter design, prefers it to several higher-end oil filter brands, and lists it as one of only three budget brands he would consider buying. Knize cites the deep filtration media pleats, which improve flow; a surprising amount of filtration media surface area; and the diaphragm-type anti-drainback valve, which is made of nitrile rubber.


Motorcraft oil filter

Motorcraft is owned by Ford and produces many OEM parts for the auto giant, including aftermarket oil filters built to OEM spec. The filters are actually made in the U.S.A. by Purolator Filters, which in turn is a subsidiary of German filter maker Mann-Hummel since 2013. The brand is known for providing innovative filters at reasonable prices.

Some cellulose filters take an efficiency hit. While Motorcraft doesn’t publish its test results, it does claim to meet the SAE USCAR-36 minimum performance requirement of filtering with 95% efficiency at greater than 30 microns. Original research by Russ Knize, however, has the Motorcraft FL-1A performing at 99.7% (single pass) and 96% (multi-pass) on SAE J806 Filtration Efficiency testing, which only reports a percentage and not particle size.

One feature Motorcraft filters are known for is the integral pressure-relief valve that prevents collected debris from re-entering the engine when the oil is under unusually high pressure.

Mobil 1

Mobil 1 oil filter

Mobil 1 filters, like ACDelco’s, are made by Champion Labs. And while ACDelco makes very good filters, the general consensus is that Mobil 1 makes extraordinary ones. In fact, Mobil 1 was a favorite of many of the professionals and reviewers we took a look at. Mobil 1 filters are expensive compared to other consumer-grade filters, but not prohibitively so.

The Mobil 1 brand is well-known and highly regarded. Mobil 1’s performance oil filters deliver 99.7% multi-pass filtration efficiency and hold 28 grams of debris. By comparison, Motorcraft filters typically hold about 12 grams. MotorTrend shows Mobil 1’s Extended Performance filter as featuring 225 square inches of filtration media, more than any other brand examined, and more than most by a mile. (It’s also interesting to note that MotorTrend found the filter to be identical to the K&N Performance Gold filter.) Mobil 1 also says this particular filter can withstand nine times an oil system’s normal pressure.

Incidentally, Mobil is also our top-ranked brand of motor oil.


Wix oil filters

Wix might not be a household name, but the company brags about having invented the common spin-on oil filter and supplies OEM filters for many auto manufacturers. The North Carolina company’s filters are increasingly manufactured by parent company Mann-Hummel, though some might still be made by Champion Labs. Wix filters are generally made for standard consumer automobiles rather than for heavy-duty and performance applications, and they are made for synthetic oil. They are generally affordable, though their prices are a little high for what is thought of as a budget brand.

Wix filters sport a 99% maximum efficiency at 35 microns, and 95% at 20 microns. The specs are hard to generalize about because, as with its many OEM filters, Wix tailors its design and manufacturing to the requirements of the auto manufacturers. Knize lists Wix as one of only three budget oil filter brands he would consider, and describes Wix as "a very well-made filter."


Baldwin oil filters

Manufactured by Parker Engine Mobile Aftermarket Division, Baldwin filters are known to be reliable for heavy-duty uses like trucks. And, indeed, Baldwin is often thought of as primarily a maker of oil filters for trucks. Baldwin makes premium filters available for a premium price, but these are only at the upper range one typically finds for consumer filters.

Baldwin filters feature reliable metal and nitrile valves and high-flow filters. They have a good efficiency rating, 85.44% at 12-30 microns. Baldwin’s spring-loaded bypass valve keeps oil moving, critical in every application but perhaps particularly so in heavy-duty/performance uses.

Baldwin says that its position as an actual manufacturer rather than merely an assembler of oil filters means that it can control quality and costs with much more precision. The company says its products are built to the exacting specifications of OE buyers and other specific applications, and exceed industry standards in all cases.


Purolator oil filter

This 90-year-old manufacturer’s filters are actually owned and manufactured by Mann-Hummel in Germany. Purolator claims to have invented the oil filter, and the company name is a shortening of "pure oil later." (One reads this factoid a lot, but no one ever seems to explain what the virtue of "later" is supposed to be.)

Purolator oil filters are well-made, which you might expect from a German manufacturer, and more impressively, they’re well-made across a line of 2,000 filters. Purolator’s best filters can deliver as much as 99% efficiency at 20 microns. And they do it for as long as 10,000 miles. Many of the filters studied by Russ Knize are Purolator clones, and Purolator is the third of the three budget oil filter brands Knize says he would be willing to buy. If there’s a knock on the Purolator design, it’s that the density of the filter media causes reduced oil flow, which makes the filters generally unsuitable for high-performance applications … but others rate the flow fairly high.

Royal Purple

Royal Purple oil filters

A relatively new brand introduced in 1986, Royal Purple has quickly garnered a great reputation for high-quality, reliable filters. Royal Purple filters are manufactured by Champion Labs. The filters are heavy duty but are well-priced, perhaps only escaping the "budget" label by virtue of their very good performance ratings. Before making oil filters, Royal Purple was primarily a manufacturer of motor oil.

The filters are expensive, but enjoy a well-deserved cachet among auto enthusiasts. Royal Purple reports an extraordinary 99% efficiency at 25 microns, and it’s 80% efficient at 10-24 microns. Royal Purple are high-flow filters in spite of this filtration efficiency (efficiency is usually correlated to restricted oil flow). The filters are supposed to be usable for as many as 10,000 miles. The filtration media is 100% synthetic micro-glass, a fine material which the company says is responsible for making its efficiency numbers possible while still providing high rates of oil flow.

OEM filters

Mechanic changing oil filter

Here’s our unsurprising surprise for you, and you might have already figured it out. There are only a handful of actual oil filter manufacturers, and many of those make OEM filters. Holding all the variables at reasonable levels — a vehicle that’s in reasonably good shape, subject to mature driving habits and a steady oil-changing routine, etc. – you will always be rewarded with acceptable performance from your vehicle’s OEM oil filter.

The reason is simple enough: OEM oil filters are invariably manufactured to the specifications of the automaker. The automaker has a lot to lose from poor OEM filters, and the OEM filter manufacturer has a lot to lose if the automaker gets dissatisfied with its work.

A little research will tell you which OEM filter your particular car takes, and whether rebranded but otherwise identical filters are available. Do, however, take care when buying online, as counterfeit OEM products are increasingly common.


Bosch oil filters

If there’s a real consensus about anything in the automotive oil filter industry, it’s that Bosch makes very good, surprisingly affordable oil filters. Prior to 2013, Bosch filters were actually manufactured by other companies, but Bosch now makes their own.

Bosch filters are extremely well-made and precise, in the German mode. Their capacity ranges from 13 to 29.1 grams, but is generally cited as 14 grams. Bosch filters are mostly 99% efficient at 40 microns. Bosch Premium filter is 99.9% efficient and filters down to 20 microns. It accomplishes all this with a relatively unimpressive 133 square inches of filter medium — about on par with Purolator, but far below some companies with worse efficiency numbers. The Bosch Premium filter’s capacity of 14 grams won’t win any awards, but it’s also not uncommonly low. The filters use an "exclusive" blend of cellulose and glass fiber (presumably different from FRAM’s "proprietary" blend).