Written by: Trevor Mahoney
Last updated: April 17, 2025
Buying a vehicle isn’t cheap. For most of us, it’s among the most expensive purchases we’ll make. When you’re spending a large amount of hard-earned money, you’ll naturally want to make your new car feel like your own.
For some, this simply means getting to know how it works and taking great care of it — everything from routine maintenance to regular services and filling up with the best-quality fuel. For others, it means they want to customize it, adding performance enhancements and other modifications. $390 billion is the projected value of the US automotive aftermarket, according to HedgesCompany.com, the automotive market research company. That’s all well and good—and it’s certainly easy to understand the temptation—but car mods are a common cause of warranty coverage being denied.
With one in three US drivers unable to afford unexpected repairs and relying on warranties for peace of mind and to provide protection from the highest costs, it’s important to get clear on what can be covered under an auto warranty — and what can’t.
Find out more about the various ways you can protect your vehicle, or read on to find out how to get extended warranty protection for modded vehicles.
What Counts as a Modified Vehicle?
A modified vehicle is one that has been altered from its original factory specs, whether for performance, comfort, or just aesthetics. Performance modifications can include upgrades like enhanced suspension or a more powerful exhaust system, whereas comfort-focused changes could look more like adding step rails to make entry easier for those families that have young children.
Many modifications are also made strictly for visual appeal, thereby allowing owners to personalize the look of their vehicles. Some manufacturers and authorized dealers provide official upgrades too which are designed to integrate seamlessly with the vehicle. However, drivers typically have the option to purchase aftermarket parts from third-party suppliers to further customize their vehicles to suit their preferences. There are just warranty considerations which may come into play.
What Does the Law Say?
The Magnuson-Moss Warranty Act outlines the specific circumstances under which a vehicle warranty may be voided, either in full or in part. According to this federal law, vehicle owners aren’t required to use OEM parts for repairs or modifications. With that said, if an issue arises due to an aftermarket part, the warranty provider is not under an obligation to cover the repair costs that may be associated with that specific component. Additionally, the Federal Trade Commission clarifies that the burden of proof falls on the warranty provider, meaning they must demonstrate that the aftermarket part is what directly caused the problem if they want to deny coverage.
This provision offers significant protection to drivers who want to customize or upgrade their vehicles, thereby ensuring that warranties cannot be unfairly voided simply because non-OEM parts were used.
What Does It Mean for Drivers of Modified Vehicles?
If you’re thinking about modifying your vehicle, it’s crucial to understand how these changes might actually affect your warranty. Before making any modifications, it’s always best to check with your warranty provider to clarify what is and isn’t covered. In many cases, aesthetic or performance upgrades, such as custom paint jobs, suspension lifts, or aftermarket wheels, won’t automatically void your entire warranty. However, the specific aftermarket parts you install may not be protected, and if a modification leads to damage in another area of the vehicle, such as the powertrain, your dealership warranty provider may deny coverage for those repairs.
For example, if you install a turbocharger to boost your engine’s power and it causes excessive wear on the transmission, your warranty or service contract provider may refuse to cover transmission repairs, even if the rest of the vehicle remains under bumper-to-bumper warranty. Similarly, an upgraded sound system may not affect your engine warranty, but if electrical issues arise due to the installation, the repair costs could fall entirely on you rather than an aftermarket warranty contract.
To avoid unexpected expenses and cover repairs, it’s a smart move to ensure that any modification work comes with its own warranty from the manufacturer or installer. Some extended car warranty or factory warranty providers also offer extended coverage for certain modifications, though this often comes with an additional surcharge. While it may cost extra upfront, opting for coverage on modifications or add-ons can provide valuable peace of mind, ensuring that if the modified part fails or causes issues, you won’t be left paying out of pocket. By taking these precautions, you can enjoy personalizing your vehicle while minimizing financial risks.
Getting an Extended Warranty for Modified Cars
For extended warranties, it’s a little different, and significant performance-transforming modifications such as installing turbochargers or upgrading the suspension are more likely to make getting extended warranty protection a headache. This is why you need to read the fine print or FAQs of your contract when you get a protection plan.
There are some popular modifications that a vehicle service contract or warranty plan covers, such as:
Making approved upgrades
Some upgrades are offered by manufacturers or an authorized car dealership, and these are likely to be within the terms of an extended warranty. Approved upgrades typically occur when there are certain parts which are approved of by the manufacturer and meant to bolster the overall function of the vehicle. Those offering the approved upgrades are also typically heavily vetted by the manufacturer ahead of time as well, meaning a warranty covers the scope of the upgrades in most cases.
Changing the size of your tires
Whether there’s a look you like or you want to improve performance on the surfaces you drive on, using specialty tires isn’t usually a problem for warranties. A word of caution: it pays to think whether the new tires will actually improve performance for all your driving. For instance, how will ride quality hold up for long-distance journeys?
Getting a lift kit
Lifting the vehicle on its tire bearings by up to 4% or by 4 inches is often covered, even if a surcharge will sometimes apply.
However, we’d always recommend checking with your chosen warranty company first, as terms and conditions vary between providers and their plans. If you’re trying to choose the right coverage plan for you, head over to our buyer guide, or read our reviews of the top providers here.
Modified Cars and Extended Warranties: Your Checklist
When buying a used car:
- Make sure to inspect it thoroughly and ask the seller whether or not it’s had any modifications made – if so, ask to see the paperwork and check if they’re under warranty. The Federal Trade Commission recommends asking for an independent inspection of any used car you’re thinking about buying.
When you’re tempted to customize your vehicle:
- If you’ve already taken out a warranty, call the provider to double-check you won’t be voiding your coverage plan.
- If you haven’t got a warranty yet, consider whether the enhancements you want to make are likely to prohibit you from getting warranty coverage in future.
- Ensure any modification you get done comes with its own warranty.
Better safe than sorry applies to vehicle modifications. You don’t want to void a warranty and end up having to foot the bill, so check the small print, get in touch, and ask specific questions before taking out coverage plans. Always check the terms carefully before you sign.
Learn about extended warranty fundamentals, including what they cover and how they work, or check out our handy buying guide.
