No matter how closely secured or neatly preserved, oil has a tendency to accumulate contaminants and/or degrade over time. In automobiles, oil filters help remove contaminants from the engine or transmission oil.
Naturally, the quality of the oil filter determines the efficiency with which it does its filtration job to ensure optimal lubrication of engine parts.
As with most products on the market, there are good and bad oil filter brands. Based on historical consumer feedback, expert reviews, and industry insights, these are 15 of the worst car oil filter brands you’re better off not using. These brands have been flagged in discussion forums and articles regarding oil filter performance issues.
Fram
Fram Oil Filters’ reputation took a big hit in the early 2000s when people complained about the glued cardboard internal construction. We’d like to tell you, as many “devil’s advocates” have done, that the “cardboard” thing is a non-issue. The paper reportedly separated and clogged the oil pump, and the fallout is hardly a non-issue.
Recently, a someonewanted to know if Fram is better now, and many of the answers were negative. People complained about moisture in the filters while still in the box.
STP
According to a post on a popular car oil discussion forum, many Nissan models once had their engines replaced as a price they paid for choosing STP as their oil filter brand. The problem, according to the post, had to do with the baffling inside the filter, which starved the engines of proper lubrication until the engine failed.
Whether this claim is real or fabricated, the fact remains that STP has an infamous reputation for leaks because it doesn’t come with a silicone back valve.
Pennzoil
We found confusing mixed reviews from consumers about Pennzoil, as the brand's quality level has fluctuated over the years. You know there’s a significant problem when many users imply they’ve switched oil brands several times when Pennzoil is involved.
Also, advocates keep reiterating the lack of scientific proof that Pennzoil causes sludge, but users still complain about clogged oil passageways and bad anti-drain back valves.
Bosch
Bosch has a solid reputation earned over a century of experience in the mobility solutions industry. If you’re surprised to see Bosch named on this list of worst car oil filter brands, you’re not alone. However, there have been quality assurance complaints against some Bosch oil filters made in Mexico, usually about the inner louvers not punched in properly.
It’s bad enough that there are cheap copies of Bosch filters out there, as confirmed by a Bosch sales rep who asked a Bosch 3323 oil filter customer a series of questions to verify if the product the customer bought is an original, implying the company knows about counterfeits out there. In Bosch and Mexico’s defense, louvered filters like the 3323 usually have bad batches, no matter the brand.
K&N
Some Redditors, who also happen to be motorcycle enthusiasts, have no love lost for the K&N oil filters. One of them recounted an awkward story, where he was just lucky to avoid the slick from a rider ahead of him whose filter failed.
It turns out the rider was a K&N customer. For a long time, people praised this brand for its high flow rates and compatibility with synthetic oils. Now, it seems the quality has dropped significantly since the company passed to a new owner, and the product is now made in several countries, including Asia.
Royal Purple
The mixed reviews about Royal Purple oil filters by experts and regular consumers can be confusing enough to make car owners leave it alone just to be safe. There are just as many “Yeah” votes in defense of Royal Purple’s efficiency as the “Nays.”
The reason we're casting our votes with the “Nays” is that, ultimately, people don't trust the brand because authorized dealers don't recommend it, and the quality has reportedly gone downhill since the owner died and RP passed to a new owner. We saw pictures of the product with epoxy resin right from the box.
AC Delco
Remember Fram, the first brand we mentioned on this list? The many complaints by ACDelco users are traceable to when Fram took over the manufacturing of ACDelco car oil filters from Champion Labs.
For example, Corvette Forum user Kent1999 shared how ACDelco filters worked like a charm on his family's various GM models until around 2016, when all four cars with ACDelco filters leaked oil. Just around that time, a concerned Beretta Chevy Owners forum user warned that ACDelco now makes all its filters ending with the “E” prefix with plastic internals, posing durability concerns.
Mobil 1
Mobil 1 used to be the brand car owners said they'd switch to when annoyed by other oil filter brands. Sadly, Mobil 1's quality has deteriorated significantly with time, and it doesn't help that it is one of the most expensive oil filter brands on the market. They're still great with synthetic oils and engine protection, but some consumers have reported leaks and bypass valve failures in rare cases.
A Mercedes-Benz M-Class owner posted a picture of a collapsed Mobil 1 filter just after 3,000 miles. The customer never got a reply from the manufacturer, and his experience can make the rest of us conclude that all aftermarket filters are substandard.
Purolator
Online oil filter communities have mixed reviews of Purolator oil filters, with some praising the brand’s affordability while others raised concerns about the build quality and filtration efficiency. We found many forum threads where users said their Purolator lost its ability to filter oil because they found holes in the media.
For example, Knfenimore from CarTalk Community shared a similar experience after replacing his Toyota Camry’s filter cartridge at 25,000 miles; he had to swap the same every 1,000 to 5,000 miles from then on as they kept collapsing.
Wix
On a normal day, both experts and users speak well of Wix oil filters, happy with their high-quality construction and effective filtration performance. In fact, we came across several people who justify the brand’s premium price with claims that Wix is one of the top choices for oil filtration. However, we had to dig deeper when we encountered a few narrations of how the filters popped for no justifiable reason.
Apparently, Wix filters do not have bypass valves, putting them at risk of pressure build-up and bursting. Even products with bypass valves need them to open optimally or risk lubricating the engine with contaminated oil. Worst still, there are fake Wix filters sold on Amazon.
Motorcraft
Motorcraft is Ford's original equipment manufacturer (OEM) filter brand, trusted by Ford owners for this reason. Unfortunately, Motorcraft has joined the infamous family of oil filter brands flagged by users and, in some rare cases, Ford dealerships.
There’s a story on Crownvic.net where the filter burst just blocks away from a Ford dealership as the vehicle left the property after an oil change. Surprisingly, the dealer admitted the same had happened several times already. Some blamed the problem on the SAE50 oil used.
Champion
Champion Labs is behind a range of oil filtration products, some of which we’ve already mentioned in this list of worst filter brands, including STP, Royal Purple, Mobil 1, and ACDelco filter models.
That said, Champion wants to have a fighter brand for any class of filters on the market, a mission they've seemingly pursued with low-cost products mainly targeted at auto repair shops and quick lube outfits.
SuperTech
SuperTech is the poster child of budget-friendly oil filters you can grab at Walmart. Granted, many users find them satisfactory for their needs, especially considering their low price point and easy Walmart accessibility.
However, we've seen just as many complaints about SuperTech’s effectiveness in providing adequate engine protection. We watched a cringe-worthy YouTube video posted on ToyotaNation showing how a SuperTech filter used on a 4-cylinder engine Camry turned into the worst decision the owner could've made.
Quaker State
Perhaps, the most alarming review we read about Quaker State is a warning by “andyf” in the Houzz discussion forum. While checking them out at the shop, all the filters he opened and ran his fingers through their thread hole had steel particles and a coat of gray film. Imagine the damage a filter like that could’ve done to his engine’s crankshaft.
Notably, Purolator, which already has a seat on this list of inferior oil filters, is the manufacturer behind Quaker State, which says a lot about the product.
Castrol
Castrol is a famous brand of oil filters. Again, they’re made by Fram, another product already sitting pretty on this infamous list. Many people recognize Castrol as a good oil brand, but that does not automatically make their filtration product just as good.
Some users have reported issues with the filtration efficiency and a perceived lack of durability. Just being a Fram product is enough to deter drivers in the know.
A brand's quality perception varies by individual experiences, so we reiterate that this list is based on customer feedback and expert reviews and not personal opinions.
