Engine Oil Filter Study

[ Disassembly and Measurements | SAE Tests | Mopar Conversion Table | Conclusions ]

Someone mailed this to me (accidentally deleted their message so I can not give proper creditr for this). Do not email me with questions since I did not author it. Sorry!

It was originally authored by Russ W. Knize, his web page is http://members.xoom.com/minimopar/oilfilterstudy.html

PRINTING ISSUES:

If you have trouble with colors when printing this or any other page, use the color override option on your web brewer. For more information, see the Printing On This Site page. I have been pondering switching the site to a printer-friendly color scheme, but that would be a HUGE project, at this point.

UPDATE:

Please read the new Warning section now.

A few people out there are helping me by sending filters. Many thanks go to them. I am happy to cut open and evaluate filters of the same type for brands that I have not tested, but I really don't want to try to cover all of the types for other vehicles. The scale of this project has already exceeded my original intentions, but I really want to finish it.

I have a special feature page for Mopar because that is why this page is here in the first place. The Audi/VW special feature is in progress because I cannot compare the German filters to the Ford 5.0L filter (they do not manufacture a true equivalent). The majority of those filters were sent by XXXXXX, at his expense. The VW/Audi/Volvo crowd has been helping me out a lot, so I am featuring their coveted filters here.

I encourage anyone out there to repeat this study for their own type of vehicle. Perhaps we can all network our studies together. This may be the beginning of a a major wake-up call for oil filter manufacturers. We're watching you!!!

Other changes are coming, including information on the European AC Delco filter.

NOTICE:

I have been getting flooded with email about this page and simply cannot answer everyone, so I apologize if your email has gone unanswered. I have been very busy lately and so updates to this site have been scarce. I have received many requests for other filter studies. Some of the requested filters are on their way and I will hopefully be able to add them to this page soon. Here is the list of filters I intend to add, assuming I can find them all (“?” means I don't know the part #, "o" means I now have this filter):

-- AC Delco PF2L

o Amsoil SDF-15 - acquired, ASF series has been discontinued

-- Bosch - no direct Ford 5.0L cross-reference (see VW feature)

-- Champ ?

-- Fram HP1 - acquired

o Hard Driver HD01 - acquired

-- Hastings LF115

-- K&N ?

-- Purolator HP1/L390001 - acquired

-- Mann - no direct Ford 5.0L cross-reference (see VW feature)

I have cut open all the filters I have acquired so far, but I have not torn them down completely because I need to take pictures. I won’t be taking pictures until I have acquired more of the filters listed above. I do not intend to look into any filters for other types of vehicles. I chose the Ford 5.0L filter because it can be used for several other engines and is quite large in size, which improves the relative surface area data between manufacturers.

I have had a couple of requests from people wondering what my qualifications are. Quite frankly, I am just a concerned automotive enthusiast that is tired of being toyed with by these manufacturers. In reality, I am an Electrical Engineer with no qualifications in the area of filtration analysis. However, I have eyes and some common sense, which has proven to be enough to accomplish what I set out to do.

Feel free to link to this page.

Happy filtering!

XXXXXXXXXXXX

Warning!

These pages are NOT to be taken as gospel. The primary motivation behind this study was to provide information about what oil filter brands are made by which manufacturers. The secondary motivation was to uncover some of the obvious internal construction issues of these manufacturers. This "study" is not a "test". The SAE J806 and J1858 tests were designed to test the filtration capability of these filters, but unfortunately they have several short comings. These include issues such as anti-drainback valve functionality (valve train noise, etc.), filter element containment capability (how long before it blocks and bypasses--related to surface area), and many testimonials that appear to point in the direction of certain manufacturers. It has been my hope to shed some light in the direction of these issues. While my infamous "two eyes and common sense" approach may not be the most scientific, it is the best I could do considering there was no personal return on the investment of time and money I put into it.

The primary shortcoming of this study is the small sampling size. I only tested the Ford 5.0L filter. It has come to my attention that some brand names use different manufacturers for different applications. Another shortcoming is the lack of testing of the filter element media itself. Unfortunately I have neither the time nor resources to do this.

I invite anyone with the means to take a larger sampling size and conduct a more complete study, which may include private SAE tests. I also invite anyone to repeat a study similar to this one on other model filters.

With all of that said, please make your own judgements. Use this study only as a source of some information that may give you a better idea about which filter brands to steer clear from. It should be obvious that some manufacturers are not being honest about their product. The next time you buy a filter for your car, buy two and hack one open to see what you have. My intent was to give you some information and alert you to some little-known issues, not to tell you what to think.

Description

One weekend I set out to every auto parts store in my area and bought every brand of oil filter I could find. I chose to get the filter for the early Ford 5.0L V8 engine. The reason is that this is a popular filter, it is large so that I can unveil any fake miniature internal components, and it fits on most 2.2L and 2.5L engines. Design-wise it is fully compatible with our oil systems and is an excellent replacement for the pathetic filter that was designed for our engines. I was able to find 20 different filters spanning several brand names. They are (in alphabetical order):

AC Delco Duraguard PF2

AC Delco Duraguard PF2L

AMSOIL SDF15

Car And Driver SF-1A

Champ

Deutsch D539

Deutsch D545

Fram Extra Guard PH8A

Fram Tough Guard TG8A

Fram Double Guard DG8A

Hard Driver HD01

Mobil 1 M1-301

Mopar 4105409

Mopar 5281090

Mopar 3549957

Mopar 53020311

Motorcraft FL-1A

NAPA Gold 1515

Penzoil PZ-1

PowerFlo SL30001

ProLine PPL-30001

Purolator Premium Plus L30001

Purolator Premium Plus L390001

Purolator Pure One PL30001

Quaker State Q58A

STP S-01

Wix 51515

I hope to add more brands to this study as I can acquire them. The analysis is sorted by brand name in alphabetical order. In each brand section, I have broken the information down into the brand name models, sorted by price. Pictures coming soon!

Disassembly and Measurements

Basically, I cut open each filter on a lathe and took measurements of many of their attributes. Simply cutting them open revealed some very interesting (and disturbing) information.

The sections below detail each of the filters I tested. A summary of the measurements I took can be found in a table for each. I noticed that other filter part numbers for the same brand were designed a bit differently. This is probably because of the shape of the can and the requirements for that engine. Here is a description of each table entry:

Average Retail Price	The average of all the retail prices I found for this filter (to the nearest $0.50)
Cartridge Length	The length of the filter cartridge, including end caps
Cartridge Outside Diameter	The outside diameter of the filter cartridge element pleats
Cartridge Inside Diameter	The inside diameter of the filter cartridge inside support tube
Cartridge Pleats	The number of pleats (or folds) in the element while in the cartridge
Cartridge End Cap Type	The type of material used to construct the end caps
Anti-Drainback Valve Type	The valve design and construction material
Bypass Valve Type	The valve design and construction material
Element Type	The type of material used to construct the filter element and the seam seal
Element Length	The overall length of the element when removed from the cartridge and stretched out
Element Width	The width of the stretched-out element
Element Surface Area	The calculated surface area of the cartridge using the above two values
Shell Thickness	The thickness of the metal used to construct the filter's shell
Backplate Thickness	The thickness of the metal used to construct the filter's backplate
Gasket Type	The type of material used to construct the backplate sealing gasket (O-ring)
Hydrostatic Burst Pressure	The amount of pressure that the filter case can withstand for a short duration without failure.
SAE J806 Filtration Efficiency	See the SAE Tests section for more details on this test.
SAE J1858 Filtration Efficiency	See the SAE Tests section for more details on this test.

The construction of the anti-drainback and bypass valves is an important feature. Many are made of nitrile rubber. As long as they have good sealing surfaces, they generally work fine. However, nitrile rubber gets stiff in extreme cold and will likely fail to seal in those conditions. Silicone rubber seals or steel valves are not prone to this. Many bypass valves are spring-loaded steel and work well. Some are spring-loaded plastic and are often not molded well enough to make a decent seal, allowing oil to leak past them.

Probably the most important value here is the element surface area. This determines the amount of filter media that is available to trap particles. The smaller the area, the sooner the filter will become plugged and will end up bypassing much of the oil instead of filtering it. More pleats in the element does not necessarily mean more surface area (as you will soon see). In fact, too many pleats can end up restricting the flow too much because there is not enough space between them to allow oil to flow.

The shell and backplate thickness are only relevant if your engine’s oil system operates at unusually high pressures. Even the cheapest filters have to be strong enough for stock oiling systems, or they will not pass SAE tests.

The SAE filtration efficiency tests are from the manufactures, and are only available for the filters I could find the information for.

Other measurements and values are debatable and I will allow you to draw your own conclusions from them.

SAE Tests

All filters have to pass SAE (Society of Automotive Engineers) tests to prove that they can truly filter out small enough particles. There are two tests available for automobile engine oil filters. All filters must pass the J806 test, but the new J1858 is much more meaningful. Currently the J1858 test is optional. Really, it's a way for high-end filter manufacturers to show off their great filters.

The SAE J806 test uses a single-pass test, checking for contaminant holding capacity, size of contaminant particles trapped, and ability to maintain clean oil. As an amendment of the J806 test, the multi-pass test also looks for filter life in hours, contaminant capacity in grams, and efficiency based on weight. The efficiency of the filter is determined only by weight through gravimetric measurement of the filtered test liquid. Typical numbers for paper filter elements are 85% (single pass) and 80% (multi-pass).

The SAE J1858 test provides both particle counting and gravimetric measurement to measure filter capacity and efficiency. Actual counts of contaminant particles by size are obtained every 10 minutes, both upstream (before the filter) and downstream (after the filter), for evaluation. From this data filtration ratio and efficiency for each contaminant particle size can be determined as well as dust capacity and pressure loss as a function of time. Typical numbers for paper element filters are 40% at 10 microns, 60% at 20 microns, 93% at 30 microns, and 97% at 40 microns.

AC Delco

Duraguard PF2

Some years ago, a study was done on oil filters that uncovered the Fram filter farce. They named AC Delco’s filter to be one of the better models. Later, AC Delco changed their design and went to a cheaper setup made by an offshore manufacturer. Even so, I definitely recommend this filter over the design of any Fram filter. In fact, I even recommend it over the low-end Wix and I (personally) prefer it over the Purolators.

The filter cartridge has a large outside diameter with deep pleats, which gives the filter element the maximum flow possible. At first glance, it appears to have little filter element media, but the surface area measure was suprising: 315 sqin. The unit had a solid top end cap because the bypass valve is at the bottom, which is a well-constructed spring-loaded steel with a nitrile seal design. The nitrile rubber diaphram-type anti-drainback valve doubles as the seal between the bypass valve and the cartridge. The only drawback to this design is that the bypass valve seats metal-to-metal against the backplate. This could allow oil from the clean side of the filter to seep back into the oil pan, but it won't allow the dirty oil in the filter to seep back. Oil that is in the main gallery usually leaks out through the main bearings anyway while the engine sits. This is a better alternative to the high-end Wix, which can allow oil to seep from the dirty side of the filter to the clean side.

The telltale signs for an AC Delco filter are: 5 large holes for the oil inlet and 6 spot welds on the rim surrounding them. There are no crimps holding the gasket in place. When you look through the inlet holes, you can see the metal bypass valve with its 12 small holes and the black anti-drainback valve diaphram around it. Through the center outlet hole, you can see the spring for the bypass valve.

Exploded view:

Average Retail Price	$3
Cartridge Length	4.625 inches
Cartridge Outside Diameter	3.375 inches
Cartridge Inside Diameter	1.375 inches
Cartridge Pleats	36
Cartridge End Cap Type	Stamped steel
Anti-Drainback Valve Type	Nitrile rubber diaphragm
Bypass Valve Type	Spring-loaded steel
Element Type	Paper media, glued seam
Element Length	70.0 inches
Element Width	4.500 inches
Element Surface Area	315 square inches
Shell Thickness	0.015 inches
Backplate Thickness	0.100 inches
Gasket Type	Nitrile rubber
Hydrostatic Burst Pressure	Unknown
SAE J806 Filtration Efficiency	Unknown
SAE J1858 Filtration Efficiency	Unknown

AMSOIL

SDF15

This filter has been acquired and is awaiting disassembly.

Car And Driver

SF-1A

This filter is a Champion filter with the one-piece filter cartridge and the fragile paper filter element.

Average Retail Price	$3
Cartridge Length	4.000 inches
Cartridge Outside Diameter	3.250 inches
Cartridge Inside Diameter	1.625 inches
Cartridge Pleats	54
Cartridge End Cap Type	Stamped-steel, with bypass valve
Anti-Drainback Valve Type	Nitrile rubber diaphragm
Bypass Valve Type	Spring-loaded steel, nitrile seal
Element Type	Paper media, glued seam
Element Length	87 inches
Element Width	3.875 inches
Element Surface Area	337 square inches
Shell Thickness	0.012 inches
Backplate Thickness	0.102 inches
Gasket Type	Nitrile rubber
Hydrostatic Burst Pressure	Unknown
SAE J806 Filtration Efficiency	Unknown
SAE J1858 Filtration Efficiency	Unknown

Champ

This filter is manufactured by Champion Laboratories, Inc. (same guys who make the spark plugs), and is sold under several other brand names. Champion admits some of these outright, and they are: Lee, Lee Maxi, and STP. Though they claim the Lee Maxi is a higher quality filter, they make no claims as to why. It sounds more like a marketing scheme to me.

The Champion design has metal end caps on the filter cartridge, with the bypass valve stamped right into the bottom end cap like the Purolator. I refer to this as a one-piece filter cartridge.

Though definitely not the same design as the Purolator, it does use the same type of leaf-spring-type spacer at the top of the cartridge and the nitrile anti-drainback valve, which doubles as the cartridge-to-backplate seal, at the bottom. The drawback to this one-piece cartridge is the rather fragile filter element paper media. It is a thin, brittle paper that rips fairly easily. It was difficult to disassemble these cartridges without destroying the filter element. One other issue is that I sometimes noticed some rust on the backplate of these filters. Since the rust is usually around by the inlet holes, any loose rust would be caught by the filter.

The telltale signs for a Champion filter are: 6 large holes for the oil inlet, one of which is larger than the others. Only the black anti-drainback valve can be seen through the inlet holes. There are 6 large crimps holding the gasket in place. Through the center outlet hole, you can see the bypass valve spring. Usually, the backplate metal is dull, or even rusty.

Deutsch

D539

This filter is a Champion filter with the one-piece filter cartridge and the fragile paper filter element.

Average Retail Price	$3
Cartridge Length	4.000 inches
Cartridge Outside Diameter	3.250 inches
Cartridge Inside Diameter	1.625 inches
Cartridge Pleats	55
Cartridge End Cap Type	Stamped-steel, with bypass valve
Anti-Drainback Valve Type	Nitrile rubber diaphragm
Bypass Valve Type	Spring-loaded steel, nitrile seal
Element Type	Paper media, glued seam
Element Length	88.5 inches
Element Width	3.875 inches
Element Surface Area	343 square inches
Shell Thickness	0.012 inches
Backplate Thickness	0.102 inches
Gasket Type	Nitrile rubber
Hydrostatic Burst Pressure	Unknown
SAE J806 Filtration Efficiency	Unknown
SAE J1858 Filtration Efficiency	Unknown

D545

This filter has not yet been acquired, but is apparently a heavy-duty version of the D539 (Champion).

Fram

Years ago Fram was a quality filter manufacturer. Now their standard filter (the radioactive-orange cans) is one of the worst out there. These filters are manufactured by Allied Signal, Inc. Please do not buy these filters. By boycotting it, we may be able to cause some change. I have personally had one if these filters fail and actually cause engine damage due to bits of paper and glue floating around in the engine.

For some inside dirt on Fram filters, see this email from an Allied Signal production engineer.

Fram Extra Guard PH8A

This filter cartridge has a small outside diameter with a rather low filter element surface area (193 sqin), and features cardboard end caps that are glued in place. The rubber anti-drainback valve seals against the cardboard and easily leaks, causing dirty oil to drain back into the pan. If you have a noisy valve train at startup, this filter is likely the cause. The bypass valves are plastic and are sometimes not molded correctly, which allows them to leak all the time, but they often leak anyway. The backplate has smaller and fewer oil inlet holes, which may restrict flow, and is made of thin material.

The telltale signs for a Fram Extra Guard are: It has 8 small holes for the oil inlet and a thin, cheap-looking backplate, and is currently stamped with a “2Y”. There are 5 very small crimps holding the gasket in place. If you look into the center hole all the way to the top of the filter, you will see a kind of “button” in the end cap of the cartridge (which looks like it's made of metal from there). This is the plastic bypass valve.

Exploded view:

Average Retail Price	$3
Cartridge Length	4.125 inches
Cartridge Outside Diameter	3.000 inches
Cartridge Inside Diameter	1.375 inches
Cartridge Pleats	34
Cartridge End Cap Type	Cardboard
Anti-Drainback Valve Type	Nitrile rubber diaphragm
Bypass Valve Type	Spring-loaded plastic
Element Type	Paper media, stamped metal seam
Element Length	47.5 inches
Element Width	4.063 inches
Element Surface Area	193 square inches
Shell Thickness	0.015 inches
Backplate Thickness	0.089 inches
Gasket Type	Nitrile rubber
Hydrostatic Burst Pressure	Unknown
SAE J806 Filtration Efficiency	Unknown
SAE J1858 Filtration Efficiency	Unknown

Fram Tough Guard TG8A

Even with all the problems of the other Fram filters, this one is not too bad. Aside from the filter cartridge, it is a very good design. Too bad Fram can’t get passed the cardboard end caps.

It has an improved filter element with more surface area (248 sqin), a heavy silicone anti-drainback valve with a good sealing surface, the same plastic pressure relief valve but with an integral screen to keep out large particles, and enough inlet holes for good flow. The only real drawback to this filter is that it is capped on each end with cardboard instead of metal.

The telltale signs for a Fram Tough Guard filter are: It has a better backplate that is usually shiny, with six larger holes for the inlet and 6 spot welds around the them. There are 6 large crimps holding the gasket in place. When you look through the inlet holes, you can see the orange anti-drainback valve. If you look into the center hole all the way to the top of the filter, you will see a kind of “button” in the end cap of the cartridge (which looks like it's made of metal from there). This is the plastic bypass valve.

Average Retail Price