The Neverending Debate On Aftermarket Parts

by Chasidy Rae Sisk

Gaps, misalignments, improper functioning…every collision repair professional recognizes the likelihood of encountering these challenges when dealing with aftermarket parts instead of OEM parts.

Yet, collision repairers often find themselves being pressured to utilize these parts based on third-party payers’ insistence that they are of “like kind and quality.” 

A simple Google search for “are aftermarket parts of like kind and quality” yields an AI overview response that reads: “No, aftermarket parts are not inherently of ‘like kind and quality’ as Original Equipment Manufacturer (OEM) parts; while some aftermarket parts are designed to meet OEM standards, many are not, and their quality, fit and durability can vary significantly.”

Those significant variances result from the way that aftermarket parts are made, through reverse engineering. This calls for aftermarket manufacturers to dismantle an original part to analyze the materials, dimensions and other details used to create their own version of the part. Although reverse engineering is a commonly accepted method, some engineers have expressed concerns with the use of this practice in the development of aftermarket parts. And that can lead to big safety concerns. 

Flaws in the reverse-engineering process can create flawed products, Dr. Kristen Wood, a mechanical engineering professor, testified during a 2009 appeal to Smith v. American Family, a class action lawsuit in Missouri. Emphasizing that function and performance are more important determinants than appearance and fit, he warned of the “real world consequences” of using aftermarket parts. 

Engineering consultant Paul Griglio made a similar argument, noting that the aftermarket manufacturing process can not attain the specifications and tolerances of an OEM part because the aftermarket specifications are derived from the original part rather than being able to rely on the specifications governing the manufacture of that part.

Ultimately, the $17 million verdict in Smith v. American Family was reinstated during the appellate hearing, with the jury determining that the installed aftermarket parts were not of like kind and quality as described in Missouri Aftermarket Parts Rule, 20 CSR 100-1.050(2)(D)2.A, which prohibits insurers from requiring aftermarket parts be used unless they are “at least equal in kind and quality to the original part in terms of fit, quality and performance” [emphasis added].

So, how can you determine if a part performs the same? Attorney Todd Tracy of John Eagle fame partnered with several collision repairers to crash-test four Honda Fits, releasing their findings in February 2018. A red 2009 Fit was repaired using unapproved procedures, while repairs on the blue 2013 Fit were performed using OEM procedures with aftermarket parts, including a CAPA-certified hood and fenders, as well as a non-CAPA certified aftermarket radiator support, bumper reinforcement bar, left and right hood hinges and windshield. An unaltered black 2010 Honda Fit served as the control vehicle, and the fourth vehicle, a light blue 2010 Fit received OEM parts and was repaired according to OEM specifications. 

All four vehicles were shipped to Karco Engineering in Adelanto, California, a crash testing facility approved by the National Highway Traffic Safety Administration (NHTSA), where they were subjected to the Insurance Institute for Highway Safety’s (IIHS) 40 mph moderate-overlap crash test. Their findings will come as no surprise to the experienced collision repair professional. 

The differences between the vehicle repaired with aftermarket parts compared to the Fit repaired with OEM parts were staggering! “The aftermarket car experienced structural failures that the other two vehicles did not,” Tracy indicated, calling the test “proof that aftermarket parts and non-OEM methods destroy safety and increase the likelihood of injury.”

Yet, the IIHS stood by its previous conclusion “that some aftermarket non-OEM parts can meet these requirements” in an advisory issued that year (available at bit.ly/IIHSFit.)

“Can” and “do” are two entirely different things. The inconsistency of aftermarket parts is well-documented. Even the Certified Auto Parts Association’s (CAPA) website acknowledges, “Quality can vary widely. Just because a part is identified for a specific make and model vehicle is no guarantee it will fit, perform, last or be as safe as the original.”

CAPA was established in 1987 to “set up and oversee a testing program to assure the suitability and quality of automotive replacement parts.” They claim their quality seal “provides proof positive that the part will fit, perform, last and be as safe as the part it replaces.”

Dr. Wood disagreed, testifying in Smith v. American Family that CAPA does not require the safety features on certain OEM parts to be reverse-engineered into the aftermarket alternative and concluding, “It is highly unlikely that CAPA-certified parts or imitation parts will be [of] like kind and quality to OEM genuine parts.”

And it’s been repeatedly proven that CAPA-certified parts fall short of meeting those standards. In 2016, Mike Parker, a collision industry consultant and the former owner of Parker’s Classic Autoworks (Rutland, VT), used a Rockwell hardness tester on ultra high strength steels components to prove “The hardness of the CAPA-certified aftermarket parts were significantly different than the OEM parts they were supposed to replace.

“The results are poorly – even unsafely – repaired vehicles,” Parker stresses, explaining why he believes aftermarket parts are not of like kind and quality. “Aftermarket parts are made by reverse engineering. They do not have the print; therefore, they do not know if the part is in tolerance. CAPA does not have the print and use their own tolerance to inspect the parts.”

In a 2019 survey conducted by the California Autobody Association, nearly half (49 percent) of respondents indicated that 75 percent of CAPA parts were not the equivalent of OEM parts in terms of fit, function and finish. Of course, since CAPA doesn’t actually make the parts, blame is easily directed to the aftermarket parts manufacturer, and when there is a recall, those companies are responsible for alerting the public. CAPA decertifies parts for this reason or if they find the part no longer meets their standards.

But what happens when a CAPA-certified part is decertified? In truth, not much. CAPA issues a public safety notice, but since they do not manufacture the product, they do not facilitate the recall, so shops and consumers may be unaware of the danger. This happens fairly frequently; CAPA had decertified nearly 60 parts year-to-date by August, transferring the impetus to perform any real action onto the shop that installed the part or has it in their stockroom.

Parker has only experienced such a notice once, related to aftermarket headlights. “CAPA sent letters out to the shops to run down the bad aftermarket headlights they installed. To do it, the shop had to look up all the Honda Accords they did, see which ones they installed an aftermarket headlight on and call the owner. How many shops do you think actually went through that process? If an aftermarket structural part was put on and it was found to be defective, most vehicle owners would never find out.”

If aftermarket parts don’t fit the same, don’t perform the same and are not recalled the same as OEM parts, it seems evident that they are not truly of “like kind and quality,” but what does that really mean? One reason these concerns persist boils down to a lack of consistency in what “like kind and quality” means. As seen earlier, Missouri specifies the need for an aftermarket part to be at least equal in fit, quality and performance to the OEM part, but other states define this in various ways. 

Rhode Island’s General Laws § 27-10.2-3 requires any aftermarket parts used in a repair to “be at least equal in kind and quality to the OEM parts in terms of fit, quality and performance.” In New Hampshire’s statutes, Chapter 407-D:3 specifies, “No insurer shall require the use of aftermarket parts in the repair of an automobile unless the aftermarket part is at least equal in like kind and quality to the original part in terms of fit, quality and performance. Insurers specifying the use of aftermarket parts shall consider the cost of any modifications which may become necessary when making the repair.”

Arguably, a part’s ability to perform the same is the most important “likeness” factor from a safety perspective, yet many states do not include performance in their descriptions of like kind and quality. Both Connecticut’s General Statutes and Vermont Statute 79-2 Section 8A reference the need for parts of like kind and quality that “conform to a reasonably uniform appearance” with no mention of how those parts might perform. In Massachusetts, 211 CMR 133.04 defines a part as being of like kind and quality if “it is of equal or better condition than the preaccident part.”

Meanwhile, since the term remains unclear, insurers often write estimates that include these cheaper components based on policy language allowing for “like kind and quality” – despite the fact that they aren’t the ones who hold liability for the repair, unless they elect to repair (which they almost never do).

“They should not co-mingle the options, but they do, on every claim,” Parker vents. “When they elect to repair, they take the keys and control scope, methodology and cost, but they are liable for the quality and safety of the repair. If they elect to settle in money, they forfeit their right to interfere with the repair contract between the owner and the shop. After they elect to settle in money, why would they have a right to dictate aftermarket parts – especially structural parts – when they have zero liability?

“If insurers are allowed to interfere with the repair contract and dictate the use of aftermarket parts, there should be laws or statutes that declare it an automatic breach of contract if the parts are proven not to be of like kind and quality,” he suggests.

Want more? Check out the November 2025 issue of New England Automotive Report!