Corolland - for owners of Toyota Corolla cars

Oil filters for the Corolla

This is the last oil filter test report update I'll be doing. I included 4 more filters and now it covers the AD-Delco, Castrol, Wix, Purolator PremiumPlus, Toyota, Fram, STP, Bosch, K&N, and Purolator PureOne.

Cutting oil filters open isn't as easy as it sounds. But when I finally got smart and pulled out the dremel tool with the cutting wheel, that did the trick. Forget using a hack-saw if you decide to do something like this. What I did was cut the case just above the seam that is located by the base-plate (I'm calling the base-plate the end that screws onto the engine - it's the heaviest plate of the filter).

This analysis covers some basic key-measures of these oil filters. Unfortunately I cannot test the paper elements themselves to determine their actual filtering measurements and this is a very important measure.

I am not an oil filter expert, I've just been maintaining my own cars probably like most of you and have been doing it since I started driving at 14, today I'm 50. I've put on and taken off a hell-of-a-lot of oil filters. I'm maintaining 5 cars right now (2 for me, wife's, daughter's, and son's). I don't know any more about oil filters, though, than you'll know after reading this report and others you might find on the Internet. I've owned a lot of cars, probably 20 or so including pick-ups. I've found Toyotas to be most excellent automobiles, really durable and well made (but you know that already) and I've owned 4 of them with 3 of those being Corollas. I think Corolla is the highest value vehicle made today, just my opinion, its a great around town car that has the capability of making fairly pleasant interstate trips and it doesn't beat you up to bad in the process.

I've bought oil filters for this report that I thought were good quality and that an average guy might use. Over the years, I've bought about every oil filter brand out there. I've never really known what was inside oil filters either, or much about how they worked. I imagine there are engineers out there that spend an entire career designing oil filters. I know a whole lot more today than I did, so its been worth the effort. I can see there is a lot of science, both design, material and production, in oil filters. Certainly more than I ever thought there was. But enough chat already, let's get to the data.

A note about my measurements: I tried to measure as consistently as possible. When measuring the filtering element, what I did was take dimensional measurements of the filter pleats and just multiply it by the number of pleats. Crude but probably pretty close. I didn't cut the element out of the filter and measure it that way though, I couldn't figure out how to do it without a tremendous amount of effort. I measured the anti-drainback valve basically out at their tips and I'm not sure this is very meaningful. And unfortunately, I couldn't take the most important measurement of all, the actual performance levels of the filtering element in the oil filter. But I really do think you learn meaningful information just by looking at different designs and components and thinking about them, and discussing them with someone else of similar interest (in my case it was my brother, a quite knowledgeable automobile guy). After you stare at them awhile, go away, then come back, etc., you'll develop some sense about them, some ideas about them.

I purchased 10 oil filters to examine; AC-Delco Duraguard, Wix, Castrol MaxPro, Toyota, Purolator PremiumPlus, Fram ExtraGuard, STP, Bosch Premium, K&N Performance Gold, and Purolator PureOne.

AC-Delco Duraguard PF1233

Base-plate (that's what I'm calling this plate that has the threads that screw onto the engine): 8 hole openings. Thickness of the plate approx. 0.110". The gasket on the base-plate that goes against the engine is round and it seems to have some lubricant inside the structure holding the gasket to facilitate easy removal of the filter from the engine block after use. Gasket is held in by a continuous circular lip. Stamped: “AA"

Case: Thickness approx. 0.015" (and I got one reading of 0.013"). There is a stamped spring in the bottom of the case.

Anti-drainback valve: Black rubber. Thickness of 0.060" with a ridge at the outer lip of 0.92". Total width of 2.10". Hole in center of 0.85". Stamped: “AAX" and “159".

The by-pass valve is at the back-end of the filter, the opposite side from the base-plate. It is a nice design, with a frame holding a coil spring, which pushes the valve sealing surface against a rubber gasket.

Filter element: Paper - thickness 0.021". 41 pleats of width 0.41". Filter element height of approx. 2.0". Approximately 67.24 sq. in. of filtering surface area. The filter element is a rectangular piece of paper like an accordion, which is wrapped around the metal support structure in the center of the filter. The two ends of the element are connected together so oil won't slip through. This filter had the two ends just glued and it didn't appear as robust as some of the other designs. Metal caps glued to each end of the paper filter element. Metal support structure inside element to prevent collapse.

General observations: Pleats were not evenly spaced, some had wide gaps between them, others were very crowded. The glue at metal end-caps was very sloppy. I did really liked this by-pass valve design best though, its pretty slick. I really like the seal that mates to the engine block being rounded too. If the assembly quality of this filter was better and the case (canister) wasn't so thin, I'd like this filter more. This filter is made in the USA. The box doesn't say which filtering standard this filter meets (J806 which is the old one or J1858 which is the new one).

Wix 51396

Base-plate: 8 hole openings. Thickness of the plate approx. 0.110". The gasket that goes against the engine is squared. Gasket is held in by a 8 pressed-in lips. Stamped: “83890R" and “2".

Case: Thickness approx. 0.017" . There is a coil spring in the bottom of the case.

Anti-drainback valve: Reddish color rubber. Thickness of 0.057". Total width of 2.10". Hole in center of 0.91". Stamped: “KD" and “46" and “5-89160".

The by-pass valve is in front of the filter next to the base-plate that is by the engine. It's a pretty good design and has a rubber seal incorporated into it.

Filter element: Paper - thickness 0.023". 49 pleats of width (or depth) of 0.365" (I changed this slightly from the first report after checking it again more closely). Filter element height of approx. 2.0". Approx. 71.54 sq. in. of filtering surface area. I could not find the seam on this filter element though I know its there somewhere. Metal caps glued to each end of filter element. Metal support structure inside element to prevent collapse.

General observations: Pleats were nicely spaced and glue job looked neat. I like this filter's coil spring that sits down inside the case better than the stamped springs I'm seeing on some of the other filters. This filter has the appearance of good overall quality. This filter is made in the USA. Its not indicated on the filter or the box it came in which qualification standard this filter meets (J806 or J1858).

Castrol MaxPro CM4386

Base-plate: 8 hole openings. Thickness of the plate approx. 0.112". The gasket that goes against the engine is squared. Gasket is held in by a 8 small pressed lips. Stamped: “88890R" and something like an “8" maybe.

Case: Thickness approx. 0.018". There is a coil spring in the bottom of the case just like the Wix.

Anti-drainback valve: Black rubber. Thickness of 0.065". Total width of 2.10". Hole in center of 0.91". Stamped: “KD" and “44" and “5-89160".

The by-pass valve is in the front beside the base-plate. It's a good one with a rubber gasket like the Wix.

Filter element: Paper - thickness 0.025". 45 pleats of width 0.35" (I re-checked this depth and adjusted it from my first report). Filter element height of approx. 2.0". 63 sq. in. of filtering surface area. I could not find the seam on this filter element though I know its there somewhere. Metal caps glued to each end of filter element. Metal support structure inside element to prevent collapse.

General observations: Pleats were evenly spaced and glue job looked neat. This looks just like the Wix filter. Its anti-drainback valve is black and not reddish, but that's probably just marketing. About the only difference I saw was the surface area of the filtering element is slightly smaller than the Wix, actually its the smallest area of any of the filters tested. No doubt this filter is made by Wix. Like the Wix, I like the coil spring this filter uses down in the case rather than a stamped spring. This filter is made in the USA. The box the filter came in somewhat indicates that this filter meets the J806 qualification (it's a little unclear).

Toyota 90915-YZZA2

Base-plate: 8 hole openings. Thickness of the plate approx. 0.10". The gasket on the base-plate is squared on one side and rounded on side that contacts the engine block. The gasket is held in place by 12 tabs. Stamped: “D".

Case: Thickness approx. 0.019". There is a stamped spring in the bottom of the case, this stamped spring looks like it has been heat tempered, which is different than any of the other stamped springs that I've seen. If it has been heat-treated it's a better stamped spring than the others.

Anti-drainback valve: Black rubber. Thickness of 0.057" but it has an outer rim that is slightly thicker than this (you almost have to see this to understand what I'm saying here). Total width of 1.85". Hole in center of 0.85". Stamped: “NOK 1.2".

By-pass valve: Located at the back-end of the filter, opposite end from the base-plate. It is a stamped metal spring design with a metal plate. Quite frankly, I cannot tell if this by-pass valve uses a rubber gasket for sealing or not. The stamped metal spring is Attached to the filtering element itself, just like the Purolator. I noticed this by-pass valve seems to take a significant amount of force to open it.

Filter element: Paper, with a thickness of 0.038". 6 groups of pleats. These pleats are arranged differently than any other filter pleats I've seen. I'm not going to say they're better, just different. You'll just have to see the photo's to really appreciate their design. They are a nice design, I don't know why they would be a better design though. Each group of pleats has 10 individual pleats. Each group of 10 pleats has pleat with width of 0.30" (6), 0.40" (2) and 0.50" (2). Filter element height of approx. 1.84". 79.48 sq. in. of filtering surface area. I couldn't find the seam for the filtering element but I know its there somewhere. This filter had cardboard end caps glued to each end of the filter element (I found this disappointing quite frankly). It had a metal support structure inside the element to prevent collapse.

General observations: This filter is probably a Purolator as the by-pass valve is a Purolator-type design. It has a nice glue job on the filter element end caps, but I don't particularly like the cardboard end-caps, though they have to work OK or Toyota wouldn't use them. I like the seal that goes against the engine block being rounded on the surface that contacts the block. The pleats of this filter are turned 90-degrees from the pleats of all the other filters (you'll have to see the photo's). This filter is made in the USA. There is no notation as to what standards this filter meets (J806 or J1858).

Purolator PremiumPlus L14476

Base-plate: 8 hole openings. Thickness of the plate approx. 0.10". The gasket on the base-plate is squared. Gasket is held in by 6 pressed lips. Stamped: “3/4-16-S" and “7".

Case: Thickness approx. 0.019". There is a stamped spring in the bottom of the case, it is stamped “2".

Anti-drainback valve: Black rubber. Thickness of 0.050". Total width of 2.0". Hole in center of 0.85". Stamped: “119".

By-pass valve is a stamped spring mounted into the paper filter end cap. The spring hold a metal plate which seals the opening. This and the Toyota by-pass valve are the same.

Filter element: Paper with a thickness of 0.021". 52 pleats of width 0.39". Filter element height of approx. 2.0". 81.12 sq. in. of filtering surface area. The seam for this filtering element was very nicely put together with a metal clasp. Metal end caps glued to each end of filter element. Metal support structure inside element to prevent collapse.

General observations: The Purolator by-pass valve seems very hard to open, I don't know that there is anything wrong with this, I just note it. The pleats in the filter were nicely evenly spaced and the glue job holding the filter element to the end caps was nicely done, and this Purolator has metal end caps on the filter element. It has the most filtering surface area too, but I would say it and the Toyota filter are equal because the margin of error in my measurements is greater than their differences. This filter is made in the USA. It wasn't noted on the filter what standard it met (J806 or J1858). Note: there was a dent on one side of a metal end-cap that was obviously done during manufacturing, but it wouldn't have any affect on filter performance in any way.

Fram Extra Guard - PH4967

Base-plate: 10 hole openings. Thickness of the plate approx. 0.12". The gasket that goes against the engine is squared. Gasket is held in place by 6 pressed lips.

Case: Thickness approx. 0.021", thickest of the group.

Anti-drainback valve: Black rubber. It seemed really thin and flimsy. Thickness of 0.054". Total width of 2.12". Hole in center of 1.0".

The by-pass valve is a plastic piece that is snapped into a coil spring that is attached to the inside case spring that resides at the far end of the paper filter element opposite the base plate (Whew!). There doesn't appear to be any gasket on this valve, just plastic against the metal of the spring creating the seal as best I can tell.

Filter element: Paper - thickness 0.036". 39 pleats of width 0.48". Filter element height of approx. 1.85". 69.26 sq. in. of filtering surface area. The seam of the filtering element was nicely put together with a metal clasp (just like the Purolator). Cardboard end caps are glued to each end of the filter element. Metal support structure inside element to prevent collapse.

General observations: The anti-drainback valve rubber was the thinnest and flimsiest of all the filters. Pretty good glue job on attaching filter element to the cardboard end caps. This filter has the grip area on the outside of the canister which makes it easier to tighten the filter by hand when putting it on the car, the only down-side I've experienced with this grip area is trying to get a filter removal tool cap over it, a really tight fit. This filter appears to be the lowest quality of the group. But it is one of the most expensive of the group too, I guess marketing costs are pretty high here. The cardboard end-caps for the filter element, the cheap plastic by-pass valve and the flimsy anti-drainback valve will make me stay away from this filter. This filter is made in Canada. I can't tell what standards it meets (J806 or J1858).

STP S4967

Base-plate: 8 hole openings. Thickness of the plate approx. 0.10". The gasket is held in by a continuous circular lip. The gasket that contacts the engine block has a rounded surface. Stamped: “AA".

Case: Thickness approx. 0.013" to 0.015". There is a stamped spring in the bottom of the case.

Anti-drainback valve: Black rubber. Thickness of 0.066" and an outer ridge of 0.092". Total width of 2.1". Hole in center of 0.85". Stamped: “AAX" and “189".

The by-pass valve is at the back-end of the filter, the opposite side from the base-plate. It is a nice design, with a frame holding a coil spring, which pushes the valve sealing surface against a rubber gasket.

Filter element: Paper - thickness 0.023". 41 pleats of width 0.41". Filter element height of approx. 2.0". Approximately 65.6 sq. in. of filtering surface area. Metal support structure in the center of the filter to prevent collapse. Metal end-caps glued to each end of the filter element. The paper filter element seam is glued together.

General observations: Pleats were not evenly spaced, some had wide gaps between them, others were very crowded and this seems to be consistently seen in a Champion made filter which I believe this filter is. The glue at metal end-caps was somewhat sloppy. I did really liked this by-pass valve design though, in my opinion it's a good one. I really like the seal that mates to the engine block being rounded too. If the assembly quality of this filter was better, i.e. the pleat spacing and the case (canister) wasn't so thin, I'd like this filter more. This filter is made in the USA. The box doesn't say which filtering standard this filter meets (J806 which is the old one or J1858 which is the new one). This filter is very similar (and I would claim the exact same) as the AC-Delco I tested, though I don't know if something about the filtering element is different, though they both look exactly identical and probably are.

Bosch Premium 3311 - $5.49

Base-plate: 8 hole openings. Thickness of the plate approx. 0.10". The gasket is held in by a continuous circular lip. The gasket that contacts the engine block has a rounded surface. Stamped: “AA".

Case: Thickness approx. 0.014". There is a stamped spring in the bottom of the case.

Anti-drainback valve: Black rubber. Thickness of 0.063" with the outer lip having a ridge that is 0.94". Total width of 2.1". Hole in center of 0.85". Stamped: “AAX" and “234".

The by-pass valve is at the back-end of the filter, the opposite side from the base-plate. It is a nice design, with a frame holding a coil spring, which pushes the valve sealing surface against a rubber gasket and exactly like the AC-Delco and STP filters.

Filter element: Paper - thickness 0.025". 46 pleats of width 0.40". Filter element height of approx. 2.0". Approximately 73.6 sq. in. of filtering surface area. Metal support structure in the center of the filter to prevent collapse. Metal end-caps glued to each end of the filter element. The paper filter element seam is glued together. [“Gabe” wrote in 2010 that Bosch used synthetic media.]

General observations: Pleats were not evenly spaced, some had wide gaps between them, others were somewhat crowded and this seems to be consistently seen in the Champion made filter, which I believe this filter is, but the pleat spacing wasn't quite as bad as it seemed to be in the AC-Delco and the STP filters. The glue at metal end-caps was a little sloppy. I do like this by-pass valve design, which is just like the AC-Delco and STP filters and in my opinion it's a good one. I really like the seal that mates to the engine block being rounded too, which the AC-Delco, STP and this filter have. This filter is made in the USA and meets the HS-806 standard (so it says on the box). Unless the paper filtering element on this filter is different from the AC-Delco and STP, other than the filtering surface-size dimension this filter looks the same as the AC-Delco and the STP.

K&N Performance Gold HP-1003

Base-plate: 8 hole openings. Thickness of the plate approx. 0.10". The gasket is held in by a continuous circular lip. The gasket that contacts the engine block has a rounded surface and the structure that hold it is lubricated to facilitate easy removal of the filter from the engine block after use. Stamped: “AA".

Case: Thickness approx. 0.021" (thicker than the other Champion-made filters). There is a stamped spring in the bottom of the case.

Anti-drainback valve: Black rubber. Thickness of 0.065" and the outer lip having a rim thickness of 0.092". Total width of 2.1". Hole in center of 0.85". Stamped: “Parker" and “10". I did notice one thing about this anti-drainback valve compared to the others like it (the AC-Delco, STP and Bosch), this valve is the same design and I'll guess that it is the same rubber material (but I have no way of knowing this), but it has a considerably deeper lip that mates and seals to the end-cap of the filter element. This would give it a better chance of staying sealed properly if oil-filter pressures were high and less chance of popping loose.

The by-pass valve is at the back-end of the filter, the opposite side from the base-plate. It is a nice design, with a frame holding a coil spring, which pushes the valve sealing surface against a rubber gasket and exactly like the AC-Delco, STP and Bosch filters.

Filter element: Paper - thickness 0.025". 49 pleats of width 0.40". Filter element height of approx. 1.95". Approximately 76.44 sq. in. of filtering surface area. Metal support structure in the center of the filter to prevent collapse. Metal end-caps glued to each end of the filter element. The paper filter element seam is glued together.

General observations: I believe this oil filter is also made by Champion and I think this is a quality filter, just a step above the AC-Delco, STP and Bosch (the Mobil 1, which is also a Champion, probably has a better filter media than this K&N, but I'm not going to cut my Mobil 1 open, I'm going to use it on the car instead and maybe I'll cut it open after I use it). The pleats in this filter were very nicely spaced, better than any other Champion designed filter I've seen. The glue at metal end-caps was a little sloppy. I do like this by-pass valve design, it is just like the AC-Delco, STP and Bosch filters and in my opinion it's a good one. I really like the seal that mates to the engine block being rounded too, which the AC-Delco, STP and Bosch also have. This filter has a 1" nut welded onto the outer case to facilitate removal of the filter by a 1" wrench. This nut also has a hole drilled in it, the idea being that if you're going to race you can wire the filter in pl ace to prevent it from ever loosening and coming off, kind of boy-racer stuff and not needed for normal service and besides there isn't anyplace to attach the wire. This is similar to how you safety wire an oil filter onto an aircraft engine (look at a Continental or Lycoming aircraft engine sometime). This filter is made in the USA. It doesn't say which standard it meets, but if you read the box the filter comes in it speaks very highly of itself. It’s different than the AC-Delco, STP and Bosch in the thickness of its case and the slightly longer lip on the anti-drainback valve but otherwise everything else looks the same at the others (I can't say about the filtering media itself, but it looks the same but there is just a little more of it).

Purolator PureOne PL14476

Base-plate: 8 hole openings. Thickness of the plate approx. 0.10". The gasket on the base-plate is squared and is a red gasket material with a slick Teflon-treated surface to ease the removal of the filter from the engine block after use. Gasket is held in by 6 pressed lips. Stamped: “X" and “3/4-16-S".

Case: Thickness approx. 0.018". There is a stamped spring in the bottom of the case, it is stamped “1".

Anti-drainback valve: Silicone. Its supposed to remain more pliable and seal better at higher and colder temperatures. Thickness of 0.041" with the outer lip having a ridge that is 0.063" thick. Total width of 2.05". Hole in center of 0.9". Stamped: “1".

By-pass valve is the typical design made by Purolator and also used in the PremiumPlus and the Toyota filter, it is a stamped spring mounted into the metal end-cap that holds the paper filter element. The spring hold a metal plate which seals the opening.

Filter element: Paper with a thickness of 0.031". 48 pleats of width 0.39". Filter element height of approx. 2.0". 74.88 sq. in. of filtering surface area. There was the funny string tied around the filter element, and tied in a knot. The seam for this filtering element was very nicely put together with a metal clasp. Metal end caps glued to each end of filter element. Metal support structure inside element to prevent collapse.

General observations: Another nice quality filter. The Purolator by-pass valve seems very hard to open, I don't know that there is anything wrong with this, I just note it, it's the design as used on the PremiumPlus and Toyota filters. The pleats in the filter were nicely spaced and the glue job holding the filter element to the end caps was OK, but a little sloppy in a couple of places. The anti-drainback valve in this filter is probably the best of the filters tested I would guess in that its silicone. The lubricated gasket which contacts the engine block is a nice feature, removal should be easy (but I don't find the other hard to remove). This filter is made in the USA. It wasn't noted on the filter what standard it met (J806 or J1858).

So What Does It All Mean

Like most things in life, oil filter design, material selection, and manufacturing are a series of compromises. Any of these filters would work for me except for the Fram ExtraGuard, I just don't care for it as they seem to have made to many compromises to lower manufacturing costs (read questionable quality). But the best value for you will be dictated by your particular needs when choosing an oil filter. As an example, I change my oil between 2,500 and 3,000 miles so any of the 9 filters should be adequate for this duration. If I were going for longer oil change intervals, however, I would recommend using one with the maximum filtering area filters.

The actual filter media in the oil filter itself, which is so important, I cannot test. I do have an idea of how I can test the filter media, do it in a somewhat crude way, but I want to investigate this a little further before beginning this experiment as it will take several months to complete (more later about this after I think it through a little more). My assumption is that if a filter meets the standard of the J806 it is filtering adequately, and if it meets the J1858 tests, a more stringent test, it's even better yet. It would take some work to find out which test most of these filters meet and I haven't done that as yet.

There are only so many oil filter companies out there. They for the most part supply about all the brands available. The ones I know of are Champion, Wix, Purolator, Fram, and I thought AC-Delco. The reason I'm not so sure about AC-Delco is the filter I tested appears to be made by Champion. AC-Delco could just sub this particular filter out to Champion though, I don't know. I know I've probably left some companies out and I apologize for that. When you see a Castrol or Penske on the shelf, its probably a slightly lesser version of a Wix. When you see an STP, its probably a lower-end version of a Champion. Interestingly, on the STP container box was the word Deutsch D368, I expect that this and the Deutsch filter for the Corolla are the same. My understanding is that Champion also makes Mobil 1, one of the best, if not the best, filters made and in general distribution. I have read that Champion makes the Mobil 1 anyway, I don't know it for a fact - but it does have the same by-pass valve that the AC-Delco, STP, Bosch and K&N have so they look like they're inbred to me. Toyota filters are made by Purolator, Mopars are made by various people, Motorcraft I think are mostly Purolator, etc. etc. The thing I guess you have to watch for in a re-badged filter like a Castrol or any of the car company brands is that they can change and you don't know it, they can go to a cheaper design next year if some company offers them a better deal. I've heard of this happening.

The low-price buy OK, if you're looking for a good price and you're going to change your oil pretty frequently the Castrol looks like a good deal at $2.00 and the STP is OK too. I guess I'd choose the Castrol over the STP even though it had slightly less filtering surface area in the filter element. I liked its coil spring which keeps the anti-drainback valve tight against the base-plate, the anti-drainback valve itself looked a little more substantial with a slightly greater depth to the lip that contacts the metal end-cap of the filter element, the filter element had nice and even pleat spacing so had a better quality look to it, and the case side-wall thickness was greater. If I didn't change my oil as frequently as I do (every 2,500 to 3,000 miles) I probably wouldn't use a filter with less than about 70 sq. inches of surface area in the filter element.

I like the Wix filters and design, and I've used these filters quite often. The one thing I see that recommends the Wix over the Castrol (both are made by Wix) is the larger surface-area for the filtering element in the Wix. I can't tell if the Wix filter media is superior to the Castrol's and they are close enough in thickness that I would claim they're both within the measurement tolerance range that I can hold for thickness (i.e. - they're both probably the same thickness but I just measured them a couple of thousands' differently). The filter media looks the same. The Wix had the pretty reddish color anti-drainback valve and there could be something in this that makes it superior, I just don't know. The metal clasp that held the paper-element seam together, over and above just gluing it, shows quality and the Wix, Castrol and both Purolators had this. I guess you pay your money and make your choice. To me, both are acceptable, the Wix is just a little better.

I did some re-measuring today on the AC-Delco, the Castrol, the Wix, the Purolator PremiumPlus and the Toyota filters. I slightly altered the measurements of the filtering surface areas of the Wix and Castrol after a little more careful measuring. I had done a pretty good job on the AC-Delco, Purolator and Toyota filters so didn't change them from my original measurements. I found that after I did several filters I kind of standardized myself in how I was approaching it which is a good thing for consistency of measurement.

If you're wanting the maximum filtering surface area look at the Purolator PremiumPlus at $3.49, the Toyota filters at $6.95, and the K&N at $9.94. (Note: $6.95 is what I paid for the Toyota filter, but I found it for $4.24 delivered from a dealer I learned about on Corolland.com - so this makes this filter a much better deal). The Purolator PureOne and Bosch are both fairly close. The Purolator PremiumPlus, Toyota, K&N, Purolator PureOne, Bosch, and Wix all had over 70 sq. inches of filtering media too, and I've kind of made 70 sq. inches of filter element surface area the dividing line (and keep in mind the Purolator PremiumPlus and Toyota were way over at approx. 80 sq. inches).

Filter-element media thickness is an interesting measurement, and one I surprisingly found somewhat difficult to make. So my measurements are a close approximation I would say. It sounds reasonable to surmise that the thicker the media (within reason of course) the better the filtering media. I do not know this for a fact, I'm just guessing here. But if this is true, then the Toyota (thickness of 0.038"), Fram (thickness of 0.036") and the Purolator PureOne (thickness of 0.031") would be the best. Getting the Toyota filter for around $4.25 makes it the best deal as far as media thickness is concerned.

As far as the anti-drainback valves, the Purolator PureOne silicone is probably the superior one. All the others look totally adequate for the job too, I don't know of any issues with any of them. One note about the Fram though, it was the flimsiest of the group and I have heard issues with it and I've personally experienced some start-up noise on one of my engines where I was using a Fram. I changed the oil filter to a different brand and haven't experienced this noise since (this was on my Jeep Cherokee). I believe the Fram anti-drainback valve isn't as good as the others.

I believe Champion makes several of these filters: the AC-Delco, STP, Bosch and K&N. I like the by-pass filter design that is used on these filters, it works nicely and has a rubber gasket for good sealing. K&N definitely is the best of this group, it has the filtering surface area, nice spacing between the filtering pleats (good quality) and a nice thick case. It also had a little better anti-drainback valve as I noted earlier. It is pricey though at $9.94 and I wouldn't use it for myself because I just don't need the capabilities its touting, but it definitely is a good one. Unfortunately I can't say if or how its filtering media might be different. The cases of these four Champion filters, except for the K&N, were pretty thin it seems. The K&N's case thickness is very robust. I'd have a very hard time buying a Bosch at its price of $5.49 over a AC-Delco at $3.49 or STP at $2.99. The K&N is pretty sweet though, its just priced to high for me.

The Fram at $4.99 just doesn't cut it in my book. It should be in the top half of this group in quality and it isn't. But it did have nice thick paper media and that, I think, is a plus. Other things were not so good as I noted.

The Purolators are a lot of filter for the money. I will include in this group the Toyota filter too, as it is made by Purolator. The Toyota is a very nice filter design, its pleats are different than any of the other filters in this test as they are not the typical accordion style around the metal center post of the filter (the post that keeps the filter from collapsing from pressure. I don't that the Toyota is a better design, I have my doubts that it is, but it is unique none-the-less. The Purolators had metal end-caps on their filter element, the Toyota used a cardboard material for the end-caps (somewhat disappointing). The Purolators, like the Wix-made filters, use a metal clasp to hold the paper-element seam together. The Toyota due to its design doesn't have or need this and it uses all adhesives. Either of the Purolators or the Toyota filter are good quality, you can't go wrong with this group. They all had a lot of filtering surface area, robust case (canister) t hickn ess, the Toyota had a really nice gasket that sealed against the block of the engine, the PureOne had a nice one too and the PureOne also had a silicone anti-drainback valve. I don't particularly care for the Purolator by-pass valve design compared to the Champion design and the Wix design, but I definitely like it over the Fram design. Getting the Toyota for $4.24 makes it a deal even thought I don't really care for the cardboard end-caps, but they're probably fine (and what do I know anyway). If the price is competitive this is a very good filter, heck, all three are very good filters and I'd use any of them.

If I had to pick 5 out of the 10 as being the best, I would pick the Purolator PureOne, K&N, Toyota, Wix, and Purolator PremiumPlus as this group. Their prices start at $3.49 and go up to $9.94. Probably only the Mobil 1 filter is superior to the filters in this group (and the Mobil 1 I bought was over $11.00, but I wanted to try the synthetic filtering media, so what the heck). If I could definitely say that one of these filters had superior filtering ability this could definitely influence the choice of which is best. As an example, if the Toyota had superior filtering ability, that could outweight the end-caps being cardboard and not metal. Then again, I don't know that some of the others such as the PureOne, K&N or Wix don't have the superior filtering element. So I guess I have to find out more about the actual filtering elements themselves to definitely answer that question. The Purolator at $3.49 certainly strikes me as a good deal though. Oh yes, I dropped by K- mart today to pick up some glue to do some repairs on the fiberglass of my sailboat. While I was there I picked up an oil filter for our Corolla. It was a Castrol MaxPro for $2. I'll compare it and the Mobil 1 in upcoming use to see if I can tell any difference between them in normal service (and I have this idea of how to test for this, but more on that later).

Additional notes from Raja:

I just wanted to pass on that a larger oil filter can be used on 88-97 Corollas. The standard purolator filter is L14476 or PL14476, but the filter used in earlier 4a engines (and other Toyota engines) is larger and still works, the number is L/PL22821. This design is 1.01" taller and 0.46" wider, internally the relief valve opens a couple psi lower. I don't know what (if any) difference there is in filter area, but it seems to me there should be a notable increase. I've been using the larger filter for about the last 75,000 miles to no ill effect in a 1993 4afe Corolla with about 250,000 miles on it.



Corolland - for owners of modern Toyota Corollas