Auto Parts A to Z: A Beginner's Guide to What Makes Your Car Tick (2023)

from $35 BUY NOW

The purpose of anti-lock braking systems — commonly known as ABS brakes — is to keep wheels from locking up and skidding, thus assisting in bringing a car to a stop as quickly as possible.

The ABS control unit is the brains of the operation that measures brake pressure and uses wheel speed as a reference point to know when to apply and release pressure. A failure of this controller will lead to a bright yellow or orange "ABS" warning light on your dash. If the control unit is being called out as having failed, you'll want to make sure your mechanic has confirmed that a wheel-speed sensor or a brake-pressure sensor aren't the issue — the control unit is by far the most expensive and labor intensive of the bunch.

from $90 BUY NOW

Summer is coming, and the last thing you want to deal with is a dead air conditioning system in your car. The most common AC system failures relate to leaks, but if a leak cannot be found, the AC compressor might not be doing its job. Some compressors have a clutch mechanism on the pulley end that can suddenly refuse to engage, and others simply have internal seals that fail and render it incapable of building system pressure. Either way, these issues both call for a replacement unit.

from $60 BUY NOW

The responsibility of the alternator is simple. It's driven by a belt, and it supplies electricity to your car to keep things powered up as well as maintain your battery at a proper state of charge.

Most commonly, a dead alternator will lead to a red battery warning light on your dash and a loss of power in your car until it stalls and dies — sad part is, this isn't a predictable one, so when it happens, it just happens. That said, alternators can occasionally have their bearings fail, leading to a horribly annoying whining noise from your engine compartment.

from $42 BUY NOW

Axle shafts — or CV shafts — take power from your differential to your front or rear wheels (depending on drivetrain configuration). More often than not, the rubber boots fail first, which then leads to dust, dirt, and other debris making it into the joints and causing all sorts of problems.

If you start hearing an annoying clicking sound as you turn around a corner, one or both of your CV shafts may need replacing. If your mechanic says the CV boots are torn, replace the rubber boots before the shaft joints themselves get ruined.

$16 BUY NOW

If you ride around in cabs a lot, you've likely heard the telltale signs of a failed ball joint. A ball joint is a pivot point for suspension and steering linkage, and as it wears it develops play that translates into a remarkably obnoxious clunking or rattling noise that you'll hear when driving over any kind of bump in the road.

Word to the wise: You get what you pay for with ball joints, and buying the cheapest replacement part most often means you'll be replacing it again sooner than if you buy the part from a reputable brand (or better yet, directly from the manufacturer of your car or truck).

from $27 BUY NOW

When your fan stops working and you can no longer blow air around the passenger cabin, there could very well be an issue with your blower motor. This hamster-wheel-esque device is a fan that wedges somewhere behind your glove box and blows air through your vents. They can get noisy, or they can stop working entirely. If you wind up with partial function — a fan that will only blow at certain speeds, for example — there's a good chance the issue is with the blower motor resistor instead.

from $25 BUY NOW

A brake caliper is your best friend when it comes to stopping, as this is the part that clamps your brake pads onto your brake rotor in order to keep you from slamming into that other car that you didn't see coming. A failed brake rotor can seize, causing your car to pull to one side and burn through its pads, or it can sometimes start leaking brake fluid — never a good thing. Caliper rebuild kits are available, but with how cheap your average caliper is, you may as well pick up a new one.

from $7 BUY NOW

Here's one where the name is pretty self-explanatory. This little switch rests in contact with the brake pedal and is used to turn on your brake lights as needed. If your brake lights are out and you've tried replacing the bulbs already, there's a good chance this switch could have kicked the bucket.

from $20 BUY NOW

The brake rotor is one of the other key components of your braking system, and just like anything else, it can be prone to failure. Brake rotors are exposed to a huge amount of heat from friction as your brake calipers clamp their pads down on the rotor to bring your car to a halt, and if they get overworked you can wind up with glazing and hot spots that lead to a pulsing brake pedal and generally poor stopping capability. Rotors, much like brake pads, should always be replaced in pairs (both fronts, or both rears at the same time).

from $109 BUY NOW

Camshafts aren't the kind of thing that fail frequently, however they can be the victim of collateral damage if you run into an issue that causes a lack of oil pressure (or simply a significant lack of oil.) The camshaft's job is to open and close your engine's valves, letting in air and fuel, and letting out exhaust gas. If you're being told your camshaft needs to be replaced, then there's a good chance that something else has gone horribly wrong inside your engine.

from $15 BUY NOW

The more likely culprit when it comes to camshaft-related issues is this simple camshaft position sensor. This sensor tells your engine control unit which way the cam is pointed in its 360-degree rotation, in order to decide when to spray fuel into the intake manifold. Without this signal, you'll see a "check engine" light on your dashboard and you may experience the car taking a bit longer to start — and likely an increase in fuel consumption as the engine management sprays extra fuel as it tries to guess when the valves are meant to be open.

from $82 BUY NOW

In manual transmission cars, the clutch is the crucial connecting link between the engine and transmission. Through its application and release the clutch disk allows for a nominal amount of slippage so that your car's occupants aren't banged around when swapping gears. That slippage comes as a price, as over time the clutch disk (on the left in this image) will eventually wear out and require a replacement in order to keep your car rolling forward.

from $30 BUY NOW

Control arms come in a variety of shapes and sizes, and are part of the linkage that connects your wheels to the rest of your car. As you can see in this picture, they usually contain a mix of ball joints and other bushing, which are the bits that wear out somewhat regularly.

Much like with the ball joints we mentioned, you're likely to hear some clunking or knocking over bumps, and sometimes your vehicle will start to feel a bit loose and wandering when changing directions. If you're lucky, the bushings and ball joints can be pressed out and replaced individually, but sometimes you're stuck buying a complete control arm to fix the problem.

from $190 BUY NOW

The crankshaft is the place where the forces of engine combustion are turned into the rotating power to get your car rolling (yes, there's more to it than that, but we're talking basics here.) Much like a camshaft, a crank doesn't usually fail on its own. If its bearings don't get enough oil, the bearings can spin, causing damage to both the crankshaft and the engine block.

Depending on the motor, these can be reasonably priced, or painfully expensive like this one for a BMW M3, but when you add all the extra engine teardown to replace it, you're looking at a hefty bill — even on a good day.

from $4 BUY NOW

What you're way more likely to see as a repair related to your crankshaft are these oil seals. Also known as a front main seal and rear main seal, one of these seals resides at the front of your engine behind the main engine pulley, and the other is on the back end where your transmission bolts to your engine. These seals will at one point or another decide to start leaking oil onto the driveway or your pristine garage floor.

$20 BUY NOW

With the advent of power door locks comes the opportunity for an electric door lock actuator to fail, though don't worry — except for very rare circumstances, the doors can still be locked, unlocked, and opened manually. Diagnostic on these actuators is pretty straightforward. However, there is always room for poor wiring and connections to be the culprits rather than the door actuator itself.

from $145 BUY NOW

Unlike a CV shaft or axle shaft, a driveshaft is the connecting link between the transmission and rear differential in a rear-wheel drive vehicle. There are two spots where things can go wrong on a driveshaft — the u-joint, and its center support bearing. The support bearing can be replaced separately, but if a u-joint fails, you either get nasty noises from under the middle of your car, or much much worse: A driveshaft will separate and cause all sorts of unholy damage before you roll to a stop.

$90 BUY NOW

Engine control units — also known as engine control modules, ECUs, DMEs, DDEs, and the like — don't fail all that frequently, and when they do they can be a right pain to diagnose correctly. Though the baseline entry price is low, this is another part that can be miles more expensive depending on brand, so you want to be sure your mechanic knows what they're talking about before agreeing to its replacement.

from $9 BUY NOW

Of the places your exhaust is likely to leak, this is the first of two. These gaskets seal the exhaust manifold to your engine's cylinder head. Over time these gaskets degrade, and much like having a hole in your muffler, this will make your quiet compact car sound like a big piece of industrial equipment.

from $35 BUY NOW

The flywheel is the second half of the equation when it comes to transmitting power from your engine to your transmission. In the case of a manual gearbox, the flywheel is the surface that a clutch bites down on. The catch is, if a driver is abusive to his clutch, the flywheel can suffer from hot spots and glazing, which could require either refinishing or replacement. The sad part is, you won't know for sure until the transmission and clutch have been removed.