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Buying a Car: Does Your Warranty Cover Modifications?

If you’re interested in buying a car and modifying it, you might be wondering whether your factory warranty will still cover your car after you install your modifications. You might also wonder what kind of modifications you can get away with adding before you run the risk of voiding your warranty. If so, you’ve come to the right place because we have the answers when it comes to modifications and warranties.

Will Modifications Void Your Warranty?

Although car enthusiasts commonly believe that any modifications will void a warranty, the truth is a little less straightforward. In fact, a modification won’t void a warranty unless an automaker or a dealer can prove that an aftermarket part caused the need for repairs. In other words, your warranty will still be valid when your radiator springs a leak, even if you’ve added an aftermarket exhaust.

It’s important to note, however, that this is something of a gray area, as you might expect. For instance, if you add a few aftermarket parts and then suffer an engine failure, is it even possible to prove whether or not the parts played any role in the incident? In some cases, the answer is yes; in others, it’s no. Either way, we’d bet that the automaker won’t want to pay for a completely new engine if there’s any chance that the old one’s failure relates to a driver’s aftermarket add-ons.

As a result, we strongly suggest you think carefully when buying a car. If you want to make major modifications to your vehicle, remember that an automaker can blame those upgrades in the event of a huge problem, and that means you might be out of luck if you need a major warranty repair.

Which Modifications Are Safe?

Because it’s hard to know what parts might someday fail, it’s difficult to suggest that there are safe and unsafe modifications. However, we have a few suggestions for aftermarket modifications that are unlikely to void your warranty.

One easy choice is upgraded wheels. No, they won’t make your car any faster, but adding wheels is an easy way to improve a car’s styling and change the character without causing any potential issues to the warranty. Of course, there are one or two warranty concerns that may arise from upgraded wheels, but they’re some of the least likely (and least costly) problems we could imagine.

Another safe modification: upgrades from the manufacturer. While many automakers don’t sell aftermarket add-ons and go-fast parts, some brands do, and we’ve never heard of an automaker-sanctioned aftermarket accessory that voids the warranty. This includes everything from superchargers to upgrades for grilles and other trim pieces. If you install an aftermarket upgrade from an automaker, you might pay more, but you’ll have the peace of mind that your warranty is still completely valid.

It’s usually the same story with modifications installed by a manufacturer-sanctioned dealer. Be sure to ask before ordering any upgrades, but most dealers won’t install any upgrades or modifications that will void a new car’s warranty. If a dealer does install such an item, they might know of an aftermarket supplier who can provide a warranty on the upgrades you’ve selected so that you’re not left entirely without warranty coverage.

Be Smart

In the end, our best advice when it comes to modifications is simple: Be smart. Don’t install any unproven parts, and don’t install anything from a brand you’re not sure about. Even if a company has a proven track record, carefully weigh the pros and cons of your decision. After all, if such parts cause a major problem, you could be stuck without a warranty, and that means you may end up with an expensive bill.

Doug Demuro
Doug Demuro
Doug DeMuro writes articles and makes videos, mainly about cars. Doug was born in Denver, Colorado, and received an economics degree from Emory University in Atlanta. After graduation, Doug spent three years working for Porsche Cars North America. Eventually, he quit his job to become a writer, largely because it meant that he no longer had to wear pants. Doug’s work has been featured in a... Read More about Doug Demuro

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  1. A Cat D repair…damage rear nearside.. very well repaired..would the manufacturers warranty still be valid?

  2. Any information pertaining to recourse in Canada would be appreciated. I purchased a second hand Mitsubishi vehicle that was only 2 years old and had the remaining warranty transferred to me. Now Mitsubishi has voided the 10year drivetrain warranty for using after market wheels and tires for the summer. The manufacturer was notified when I brought my car in for a recall service. 

  3. I came across your blog as above, while looking for more information on voided warranties as a result of after-market fitments. I am in a dispute with Ford regarding a declined turbo warranty on a Ford Ranger, which they allege is a result of an aftermarket grille, but refuse to provide me with airflow readings with a standard Ford grille and the airflow readings with the after-market grille as substantiating proof that the grille is the direct result of the turbo failure.

    I have information that the dealerhip (as well as 2 other Ford dealerships) sends brandnew vehicles to the same fitment centre on behalf of clients before delivery of the brandnew vehicles, for fitment of the very same bodykits which our Ranger has, in other words sanctioning and condoning the fitment. Does the onus not then fall on Ford to prove that this grille has directly caused the failure of the turbo? I feel that they are hiding behind the wording of the warranty guide, which states : 

    Our vehicles are designed and tested as per Ford specifications and Product Development design intent. When you alter the operating conditions of the vehicle by modifying it, from that point on, the vehicle is operating outside the design intent.We refer you to the Customer Assistance Service and Warranty Guide Page 14, point 4 states that the “New vehicle warranty will be rendered invalid due to unauthorised modification of the vehicle”

    My enquiry to you therefore is, where can I obtain more information and specifically from a legal point, as to what my recourse will be. Thanks.


    • I’m also in dispute with Ford regarding Warranty. What a headache because I don’t know where to turn for recourse. 

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