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Check Valve

1. A valve that permits the passage of a gas or fluid in one direction but not in the other. 2. A device located in the liquid line or inlet to the drier of some systems to prevent refrigerant flow in the opposite direction when the unit is turned off.

Check-valve Relay

An electrical switch to control a solenoid-operated check valve.

Checker

A term often used for checkered flag.

Checkered Flag

1. A flag waved at a driver, in closed-course competition, to indicate that he/she has completed the race. 2. The first driver shown the flag is the winner of an event.

Cheek

The plate-like part of a crankshaft that connects the journals, often serving as a counterweight.

Chem Mill

A term used for chemical milling.

Chemical Energy

A form of potential energy released or stored during chemical a reactions.

Chemical Fire Extinguisher

A type of fire extinguisher that used dry chemicals that displace oxygen, thereby extinguishing a fire.

Chemical Gasket

A liquid or putty-like substance, similar to RTV, used as a substitute for a solid gasket.

Chemical Hazards

Hazard concerns primarily, cut not exclusively, from solvents, fuels, asbestos, and antifreeze.

Chemical Instability

An undesired condition that exists when a contaminant causes a fluid, such as refrigerant, to break down into a harmful chemical.

Chemical Milling

A term often used for acid dip.

Chemical Reaction

The formation of a new substance when two or more substances are brought together.

Chemiluminescence

The emission of light energy, other than by burning, during a chemical reaction.

Cherry

1. In unusually fine shape. 2. As good or better than new. 3. Not used before.

Chest

A tool box that sits at the front of a pickup's bed, right behind the cab, but does not extend over the bed rails. Chests come in various sizes, including low-profile designs that are no taller than the truck's bed rails. Some chests extend all the way to the bed floor, while others feature a raised center section to accommodate long loads. Also known as a saddle box.

Chicane

An artificial series of turns on a straight track, in road racing events, that are marked by pylons or temporary curbs.

Child Safety Seat

A built-in or a removable seat that enables an infant or small child to ride safely in a vehicle. Most removable child safety seats can be used in virtually any vehicle, but some are designed specifically for a particular car, pickup, SUV or van and are available as an option when the vehicle is purchased. A vehicle's seatbelt is used to secure the child safety seat, which should be positioned in the back seat, rather than the front passenger seat. This is especially important in vehicles with a passenger airbag. Once a child outgrows a child safety seat, he or she may "graduate" to a youth car seat.

Child-safety Latch

A power-door lock system that prevents the door(s) from being opened from the inside, regardless of the position of the door-lock knob.

Chilled Cast Iron

Cast iron that has been hardened using dry ice.