Making Sense of New-Car Warranties

All new cars come with warranties, from comprehensive bumper-to-bumper policies to those that cover specific components like seat belts or catalytic converters. In all, a car can leave the dealership with 10 or more warranties - which can be a mess for its new owner to wade through.

Fortunately, most of these programs cover similar components. To find the most common ones, we scoured owners' manuals and online policies for dozens of cars and trucks, and consulted with several experts. Here are 12 common warranties we found.

• Bumper-to-bumper: Often called a basic warranty or new-vehicle warranty, a bumper-to-bumper policy covers components like air conditioning, audio systems, vehicle sensors, fuel systems and major electrical components. Most policies exclude regular maintenance like fluid top offs and oil changes, but a few brands have separate free-maintenance provisions, and those that do offer them is slowly rising. Bumper-to-bumper warranties typically expire faster than powertrain warranties.
• Powertrain: Don't be misled a 10-year or 100,000-mile powertrain warranty doesn't promise a decade of free repairs for your car. It typically covers just the engine and transmission, along with any other moving parts that lead to the wheels, like the driveshaft and constant velocity joints. Some automakers also bundle seat belts and airbags into their powertrain warranties. With a few exceptions, powertrain warranties don't cover regular maintenance like engine tuneups and tire rotations.
• Extended-length: When you buy a new car, most dealerships will offer to sell you a supplemental contract that extends beyond the standard powertrain and bumper-to-bumper policies. Programs vary: An entry-level policy might carry a deductible and cover only the engine and transmission, while a deluxe package could drop the deductible and include all the trimmings of a full bumper-to-bumper warranty. Most programs are backed by automakers, though it's not uncommon for third parties to offer their own policies. Many policies can be purchased months or even years after you buy your car. Most of these policies can be transferred to future owners, which can increase your car's resale value.
• Roadside assistance: Some automakers include roadside assistance with their bumper-to-bumper or powertrain warranties, while others have separate policies. These programs cover anything from flat-tire changes and locksmith services to jump-starts and towing. Few reimburse incidental costs like motel rooms (if you have to wait for repairs).
• Tires: Like replacement tires, new-car tires are covered by their manufacturers. Depending on the type of tire, most warranties have a year or mileage limit, whichever comes first. Generally, tires are eligible for warranty replacement if the tread-wear indicators, which signal the final 1.6 millimeters of usable tread, become visible prematurely. That doesn't always mean a free set of tires; most tiremakers prorate the new-tire cost based on premature wear, meaning you'll only get reimbursed for the remainder of how long the tire should have lasted. Be sure to have your tires rotated regularly, as improper rotation, inflation or balancing can void your warranty. Unless a special policy has been purchased, basic tire warranties don't cover punctures or collision damage.
• Rust perforation: Rust coverage covers body panels that have rusted through. Such policies generally last up to six years and have no mileage limits. They only cover complete perforation, which is a relatively rare occurrence with today's rustproofing. Most policies don't provide coverage for rust caused by rock chips, hail or acid rain.
• Emissions: Since 1972, the government has required all cars to have emissions controls like oxygen sensors and catalytic converters. Two types of warranties exist: performance warranties and design and defect warranties. Performance warranties require automakers to repair or adjust emissions controls for at least two years or 24,000 miles if the car fails an emissions test. If emissions controls fail independent of a test, the design and defect warranty covers them for at least two years or 24,000 miles. Major components like catalytic converters and engine control modules are covered for performance and defects for eight years or 80,000 miles. On some items, California residents are eligible for additional coverage.
• Factory accessories: Factory accessories include everything from a fancier audio system to an engine modification from a manufacturer's performance wing. Most automakers cover accessories for one to three years or the remainder of the bumper-to-bumper warranty, whichever is shorter. Be sure to check out all the specifics; modifying the accessories after they've been installed can void your coverage.
• Batteries: If it's not covered in the bumper-to-bumper policy, a car's conventional 12-volt battery sometimes may get its own warranty. Battery warranties usually range from two to three years; they cover defective batteries on a prorated basis, so you'll be compensated only for the remaining battery life you lost. Battery warranties rarely cover maintenance or misuse.
• Hybrid components: Components in the hybrid drivetrain include the high-voltage battery pack along with the hybrid assist motor and all the electrical connections in between. Such components may be expensive to repair or replace, so automakers offer generous warranties: In many cases it is about eight years and 80,000 to 100,000 miles, whichever comes first.
• Seat belts and airbags: A lot of carmakers include seat belts and airbags with powertrain or bumper-to-bumper warranties. Others make separate provisions, and the warranties sometimes carry no expiration date. Seat belts are generally covered for operating usability only, so don't expect a replacement for discoloration or some other cosmetic defect.
• Third-party components: Sometimes equipment made by other companies, like a DVD player or wireless headphones for backseat passengers, carries a dedicated warranty from its manufacturer. Pay attention to these: They are likely shorter than the bumper-to-bumper warranty for the car.