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Design Working Pressure

The maximum pressure under which a specific system or component is designed to work safely and without failing.

Desmodromic Valves

A valve system in which positive cam action, not spring action, is used to open and close the intake and exhaust valves.

Detailer

A car care product designed for quick paint touch-ups between washes (rather than to completely wash a dirty vehicle). It will remove contaminants (such as bird droppings and sprinkler spray) before they have a chance to damage a vehicle's paint. Most experts recommend removing contaminants as soon as possible. Also the term for a person or company that uses car care products to make vehicles look as good as new again, if not better.

Detent

1. A recess to hold the gear selector in the gear range selected. 2. A pin, stud, or lever which initiates or halts an action at a determined time or interval. 3. A valve that controls downshifting by boosting throttle pressure.

Detergent

1.A chemical, added to engine oil, that possesses the ability to clean by preventing the accumulation of deposits. 2. An additive used in gasoline to prevent and/or clean up fuel system deposits.

Detergent Dispersant

A chemical component in motor oil that loosens dirt and varnish in an engine.

Detergent Oil

An oil with a detergent additive.

Detonation

A phenomenon of internal combustion where the compressed air/fuel charge explodes violently instead of burning smoothly, usually due to the creation of a second flame front in the combustion chamber, away from the spark plug. Sometimes resulting in an audible knocking noise but always harmful to the engine.

Detonation

A condition that is hazardous to an engine. When an engine detonates, the air and fuel mixture explodes a second time, after the spark plug has fired, causing a pinging or knocking sound. Naturally, an unplanned explosion is a bad thing. In severe cases, detonation can destroy a piston or an entire engine block. See also preignition.

Detonation Sensor

A device, mounted on an engine block, cylinder head, or intake manifold, that generates and sends a small voltage signal to the ECU, to retard timing, when encountering the vibration frequency associated with detonation.

Detonation-detection Sensor

A term often used for detonation sensor.

Detroit Locker

A specific brand of locking rear-end differential.

Deuce

1. A 1932 Ford. 2. A two-barrel carburetor. 3. A 1962 through 1967 Chevrolet.

Deuce

Slang for a '32 Ford, one of the most popular cars ever in street rod circles.

Deuce And A Half

A truck having a nominal payload capacity of 2-1/2 tons.

Deuce And A Quarter

The Buick Electra 225, particularly the 225-inch-long 1959 model.

Dex-Cool

A long-life antifreeze manufactured by Texaco, Used in most GM heavy and light duty vehicles, Dex-cool is an ethylene glycol based antifreeze that contains (OAT's ((Organic Acid Technology)) rather than nitrates and phosphates or silicates as corrosion inhibiting chemicals) Normilly dyed Orange to distinguish it from other Ethylene glycol antifreezes and Propylene glyco.l.

Dexcool

See Dex-Cool.

Dexron II

A petroleum-based automatic transmission fluid developed by General Motors.

DFC

Deceleration fuel control.