A part of your vehicle’s ignition system. The spark plug ignites the air/fuel mixture in the combustion chamber.

The electrode is the curved piece(s) of metal (ground electrode) that reaches over the center electrode. The spark is created between the electrodes.

Gap is the precise distance between a spark plug’s center and ground electrodes.

The terminal is the shiny metal part of a spark plug that the spark plug wire attaches to.

Spark plug wires are the thick cables that bring spark from the distributor cap to the spark plugs.

An instrument that indicates a vehicle’s speed.

Springs absorb road imperfections and vibration, help hold the suspension up, and help vehicles handle better.

The stabilizer bar is a suspension system component that helps a vehicle to stay flat and not lean excessively when cornering. Also called a sway bar or anti-roll bar.

A rubbing compound is a type of paint polish that contains extremely fine abrasive particles. These particles remove the top layer of paint, revealing the shiny layer underneath.

This is a condition that occurs when too much gas and too little air is being fed to the engine. A sign of rich running is black, sooty exhaust.

Rust-converting primer is a special type of primer that stops the progress of surface rust.

Rear-Wheel Drive (RWD). Rear wheel drive cars transmit power to the ground through the rear wheels.

A serpentine belt is a wide single drive belt that drives all the engine’s accessories (alternator, power steering pump, air conditioning compressor, etc.).

This is a series of rods and/or cables that connect the gearshift lever or gear selector to the transmission.

Shock absorbers are part of your vehicle’s suspension and contribute to your vehicle’s ride quality. They also regulate how much your vehicle moves up and down after going over a bump.

A relay is like an automatic switch. When power is applied to a relay, an internal switch closes, completing a circuit.

Reservoir is a generic term that refers to any container for a fluid. For instance, most vehicles have a windshield washer fluid reservoir and a brake fluid reservoir.

When your car is in park or neutral and you press on the gas without the intention of making the car move, you are revving the engine.

Rheostat refers to a control which varies the intensity of the lights and speed of certain accessories that it is connected to. For instance, an instrument lighting rheostat controls the brightness of the instrument lighting.

When driving along, if you rest your foot on the clutch pedal, you are riding the clutch. This practice causes excess wear on the clutch and the clutch throw-out bearing.