- Alternator
- Charges the battery and powers the electrical system while the engine runs. Fails: battery light, car dies.
- Brake pads / rotors
- Pads are the friction blocks; rotors are the discs they squeeze. Pads wear by design; rotors wear thinner and can warp.
- Caliper
- The clamp that pushes the pads. Sticks or leaks with age.
- Catalytic converter
- Cleans exhaust gases. Expensive; often blamed when something else (misfire, sensor, leak) is the real cause.
- Control arm / ball joint
- Connects the wheel to the car and lets it move. A worn ball joint can separate — a real safety item when play is measured.
- CV axle / joint
- Drives a front wheel through flexible joints. Clicks in turns when worn.
- Diagnostic fee
- Payment for the technician's time to find the problem. Ask for the findings in writing and whether it's credited toward the repair.
- EVAP system
- Keeps fuel vapors in. Leaks trigger check-engine codes; a loose gas cap is a common cause.
- Head gasket
- Seals the engine block to the head. Failure mixes coolant, oil and combustion — major repair, needs real tests to confirm.
- Ignition coil
- Makes the spark for a cylinder. Fails: misfire. A flashing check-engine light means stop soon.
- OEM / aftermarket / remanufactured
- Made by the carmaker's supplier / made by someone else / rebuilt used part. All can be fine; ask which and what the warranty is.
- Oxygen (O2) sensor
- Tells the computer how the fuel is burning. Wears out; cheap part, access varies.
- Serpentine belt
- The rubber belt that turns the alternator, A/C and often the water pump. Breaks: you're stranded.
- Strut / shock
- Controls bounce and keeps tires planted. Leaking or knocking = replace; "aged" = your call.
- Thermostat
- Valve controlling coolant flow. Stuck closed: overheating. Stuck open: runs cold, weak heat.
- Tie rod
- Links the steering to the wheel. Play = safety item. Needs an alignment after.
- Timing belt / chain
- Keeps engine internals in sync. Belts need scheduled replacement (engine-destroying if they break); chains normally don't, but can wear.
- Water pump
- Circulates coolant. Leaks or gets noisy; overheating if it fails.
- Wheel bearing
- Lets the wheel spin smoothly. Hums or growls with speed when worn; can loosen the wheel if ignored.
For the full version — urgency, what to ask, what should prove it — describe the repair in At the Shop.