The car makes a very loud, sharp squealing noise when the brake pedal is pushed. Technician A says the noise is caused by a broken Wheel Bearing. Technician B says the Brake Shoe is the curved metal plate that pushes inward against the drum to stop the wheel.

The battery warning light, shaped like a battery, is on while the car is running. Technician A says the spinning machine that makes electricity is the Alternator. Technician B says the Starter Motor uses battery power to make the engine turn over and start.

Regarding how the engine starts the fire (ignition): Technician A says the Spark Plug is the part that screws into the top of the engine and makes a tiny lightning bolt to light the gasoline. Technician B says the Spark Plug is located in the Intake Manifold (the large plastic part that supplies air to the engine).

The engine is getting too hot, and there is green liquid (coolant) dripping onto the ground. Technician A says the leak is caused by a failed Head Gasket (the seal between the block and the head). Technician B says the Radiator Hose carries gasoline to the engine.

A customer reports that air flow from the vents is very weak, even when the fan is on high. Technician A says the rectangular paper element called the Cabin Air Filter is probably clogged with leaves and dirt. Technician B says the Cabin Air Filter removes dust and trash from the air that you breathe inside the car.

A mechanic hears a loud, deep humming noise coming from the front wheel that gets louder when the car goes faster. Technician A says this noise is a sign of a failing Wheel Bearing, which is a set of steel balls or rollers that allow the wheel to spin easily. Technician B says the noise is coming from the Brake Caliper.

The engine check light (MIL) is on, and a computer code says the engine is running "rich" (too much gas). Technician A says the code means the Manifold Absolute Pressure (MAP) Sensor is broken. Technician B says the Thermostat is responsible for reading the temperature of the air entering the engine.

A driver notes that the vehicle bounces up and down many times after going over a small bump. Technician A says the Shock Absorber (the vertical tube with a rod that stops the spring from bouncing) is worn out. Technician B says the Coil Spring is the strong piece of twisted metal that holds up the car's weight.

A front-wheel-drive car makes a regular clicking or popping noise that is loudest when the driver makes a sharp turn. Technician A says this is a symptom of a failing CV Axle (Constant Velocity), the short shaft with a flexible rubber boot that sends engine power to the front wheels. Technician B says the noise means the Exhaust Manifold is broken.

When checking for a loose steering part: Technician A says the Tie Rod End is the part with a ball-and-socket joint that links the steering rack to the wheel assembly. Technician B says the Tie Rod End's job is to stop the car from bouncing up and down.

A mechanic is changing the long engine belt (serpentine belt) and needs to loosen it. Technician A says the Idler Pulley is designed to adjust the belt length to allow for installation. Technician B says the Belt Tensioner is the part designed to keep constant pressure (tension) on the belt.

Regarding how brakes get their pressure: Technician A says the Master Cylinder is the container that holds the brake fluid and uses two plungers (pistons) to create hydraulic pressure when the pedal is pressed. Technician B says the hydraulic pressure is created inside the Brake Caliper.

A vehicle's gasoline sprayers (fuel injectors) are getting blocked up often. Technician A says the problem is due to the failure of the Fuel Filter, a small part placed in the fuel line to catch dirt and rust. Technician B says the Fuel Filter is responsible for cleaning the engine oil.

When talking about modern front suspension: Technician A says the McPherson Strut is one unit that holds the coil spring mounted directly around the shock absorber. Technician B says the McPherson Strut is only a spring and does not include a shock absorber.

The engine runs cold and never gets up to its normal operating temperature. Technician A says the Thermostat (the small valve with a brass piece inside) is stuck open, letting too much coolant flow. Technician B says the Water Pump creates the flow of coolant that the thermostat controls.

During an inspection of old-style drum brakes: Technician A says the Brake Shoe is the curved metal plate with friction material that pushes outward against the drum to stop the wheel. Technician B says the Brake Pad performs this job in a drum brake system.

After an oil change, an oil leak is found dripping down the side of the engine block, near the top. Technician A says the leak is likely from the Valve Cover (Rocker Cover) gasket, which is the seal for the large cover on the very top of the engine. Technician B says the leak is from the Oil Pan.

An engine is clearly overheating (steam, bad smell), but the dashboard gauge reads low. Technician A says the small electronic Coolant Temperature Sensor might be sending a wrong signal to the gauge and engine computer. Technician B says the Oil Pressure Sensor checks the temperature of the coolant.

To pass an emissions test, the car must change toxic engine exhaust into less harmful chemicals. Technician A says this chemical change is done by the Catalytic Converter. Technician B says the Muffler uses baffles to make the loud engine noise quieter.

Regarding the parts that open and close the engine's air valves: Technician A says the Rocker Arm is the metal lever used to push the valve open. Technician B says the Camshaft is the shaft with egg-shaped bumps (lobes) that controls when and how long the valves open.

When trying to stop excessive engine shaking you can feel through the car's body: Technician A suggests checking the Transmission Mount, the rubber and metal block that connects the transmission to the car body, for cracks. Technician B says the Transmission Mount supports the weight of the exhaust pipes.

A technician needs to figure out why the engine is misfiring sometimes. Technician A says the Crankshaft Position (CKP) Sensor is the main sensor that tells the computer the exact position and speed of the engine's main rotating shaft. Technician B says the Mass Air Flow (MAF) Sensor gives the computer engine position information.

During a brake fluid leak check on a disc brake system: Technician A says a leak near the wheel is coming from the Brake Caliper, the metal assembly that holds the brake pads and contains the hydraulic piston. Technician B says the Brake Caliper holds the Master Cylinder inside it.

Regarding the two main rotating parts of the engine: Technician A says the Camshaft is the long shaft with bumps that opens and closes the engine valves. Technician B says the Crankshaft takes the up-and-down movement of the pistons and changes it into spinning movement to drive the car.