Every new car comes with a warranty, and some used cars have one, too. New car warranties are comprehensive and most cover every part of the vehicle for at least the first 12 months or 12,000 miles. After that, various warranties are offered for the different parts of a car. Used car warranties are usually limited, guaranteeing protection from defects for only a few months or a couple thousand miles – except when it comes to Certified Pre-Owned vehicles, which often extend the original powertrain warranty and provide added peace-of-mind on other vehicle systems.

Here are the most common types of new car warranties and what they cover:

A Bumper-to-Bumper warranty covers the entire car, excluding regular wear-and-tear maintenance items (unless otherwise specified). Typically, this kind of warranty covers the suspension, powertrain, drivetrain, electronics, steering, braking system, emissions systems, exhaust system, and other major parts of the vehicle.

A Powertrain warranty covers engine components such as the engine block, cylinder heads, intake/exhaust manifolds, injection systems, flywheels, crankshaft, pistons – basically anything related to the vehicle’s power plant.

The Drivetrain warranty refers to anything that drives the wheels, such as the transmission, axles, wheel hub assemblies, transfer case, auxiliary gearbox, differentials, driveshafts, clutch, pressure plate, etc.

A Corrosion warranty covers rust-through perforation of your car’s sheetmetal. Surface corrosion from nicks, chips, and scratches are not covered because this type of damage is not the fault of the manufacturer and is usually due to environmental conditions and lackluster car care. Coverage varies with each manufacturer, so check your warranty information or check with your dealer for specific details on coverage.

The Emissions warranty is separate from other warranty coverage for your car. The federal government requires that carmakers provide extended warranty coverage on emissions systems to ensure that they pollute less over a longer period of time. Typical coverage is seven to eight years and 70,000 to 80,000 miles. If you have an exhaust or emissions problem on a late-model vehicle, make sure to check with your dealer on emissions warranty coverage before paying for the repair.

Most warranties won’t cover “wear-and-tear” items, those that are considered regular maintenance items but which naturally wear out and are not the responsibility of the car manufacturer. Parts that fall into this category are fan belts, serpentine belts, filters (oil, air, cabin air, transmission), and braking components like pads, shoes, rotors, and drums. Basically, anything that has to do with regular maintenance is considered a wearable item.

There are, however, extenuating circumstances under which wearable items can be covered. For instance, if the wearable item breaks because of the failure of a covered part, such as when a brake caliper seizes and causes the brake pads to wear excessively, the wearable item will usually be covered. Another example would be a serpentine belt that fails due to a faulty water pump. In this case, the belt is usually covered.

Finally, with respect to new car warranties, remember that warranty repairs are a revenue source for the dealership, though paid at a different rate than normal repairs, so they want you to bring the car back for covered repairs. So when dealers refuse coverage, it’s not because they want to. They simply cannot agree to cover the repair based on the warranty agreement and the strict adherence to the agreement expected by the manufacturers. Lately, carmakers have been ‘trimming the fat’ and paying closer attention to profit margins. Today, every warranty claim that comes through the pipeline is scrutinized, making it much harder for dealers to slide claims in ‘under the wire’ like they used to. In the old days, when a customer’s vehicle was out of warranty by a few thousand miles, dealers would ‘fudge the numbers’ in order to get coverage for the customer. The carmaker either didn’t know the difference or didn’t care about the ‘finer details’ of the agreement. Not any more…every claim is under a magnifying glass and anything questionable is denied.