 |
|
 |
Radiator Glossary of Terms
|
|
|
A ·
B ·
C ·
D ·
E ·
F ·
G ·
H ·
I ·
J ·
K ·
L ·
M ·
N ·
O ·
P ·
R ·
S ·
T ·
U ·
V ·
W ·
|
|
|
| Deflection |
|
The deference between a tire's unloaded or free radius and the loaded radius.
|
|
|
| Defogger |
|
A device that uses hot air or electrical heat to remove fog or ice from the inside and outside of the windshield.
|
|
|
| Degrease |
|
The act of wiping down a vehicle's surface with solvent prior to a new paintjob. Degreasing is essential to proper paint adhesion.
|
|
|
| Desiccant |
|
A drying agent used in the refrigeration system to remove moisture. The moisture-absorbing zeolyte crystals are located in the accumulator-dryer or receiver-dryer depending on the type of system. R-134a systems generally require XH-7 or XH-9 desiccant.
|
|
|
| Detergents/Dispersant Additives |
|
Petroleum-product additives that help maintain engine cleanliness.
|
|
|
| Detonation |
|
An unwanted explosion of the air/fuel mixture in the combustion chamber caused by excess heat and compression, advanced timing, or an overly lean mixture. Also referred to as "ping".
|
|
|
| Detroit Diesel Two-Stroke Engines |
|
A type of engine where air enters the cylinder through cylinder liner ports and is compressed. Fuel is then injected and burned. During the power stroke, clean air sweeps the combustion gases out the exhaust.
|
|
|
| Diagnostic Trouble Code |
|
Computerized engine control systems have a certain amount of built-in self-diagnostic capability to detect problems that affect engine performance and emissions. The same is true for the antilock brake system and other onboard systems that are computer co
|
|
|
| Diaphragm |
|
A thin, flexible wall separating two cavities, such as in a vacuum advance unit or brake vacuum booster.
|
|
|
| Dichlorodifluoromethane |
|
Chemical name of R-12 refrigerant.
|
|
|
| Diesel Engine |
|
An engine that operates under the compression-ignition principle. The compression ratio in the engine is often two to three times higher than in a gasoline engine. In turn, fuel burns without the need for a spark plug to initiate combustion. The higher co
|
|
|
| Diesel Oil |
|
A fuel used in vehicles with diesel engines.
|
|
|
| Dieseling |
|
A condition in which hot spots in the combustion chamber cause the engine to run on after the key is turned off.
|
|
|
| Differential |
|
A geared assembly that allows the transmission of motion between drive axles, giving one axle the ability to turn faster than the other.
|
|
|
| Diluent |
|
A fluid used to thin out or weaken another fluid, also known as a solvent.
|
|
|
| Diode |
|
An electrical device that will allow current to flow in one direction only.
|
|
|
| Dipstick |
|
A thin metal rod marked with level indicators that is inserted into the oil sump to determine how much oil is left in the engine. Dipsticks are also used to check transmission fluid.
|
|
|
| Directional Stability |
|
The tendency for a tire to roll in it's steered direction rather than follow road contours.
|
|
|
| Disc Brake |
|
A hydraulic braking assembly consisting of a brake disc, or rotor, mounted on an axle, and a caliper assembly containing, usually two brake pads which are activated by hydraulic pressure. The pads are forced against the sides of the disc, creating frictio
|
|
|
| Disc Thickness Variation |
|
A variation in thickness between two points on the friction surface of a disc rotor (usually caused by poor manufacture, poor machining or rubbing of the rotor against the caliper when the brakes are "off").
|
|
|
| Discard Thickness |
|
Alternative term for Scrap Thickness.
|
|
|
| Discharge Line |
|
Connects the compressor outlet to the condenser inlet. Also called the "high side" line. High-pressure refrigerant vapor flows through this line.
|
|
|
| Discharge Pressure |
|
The pressure of the high temperature refrigerant vapor as it leaves the compressor.
|
|
|
| Discharge Side |
|
The part of the A/C system from the outlet port of the compressor to the evaporator inlet.
|
|
|
| Distribution System |
|
The network of passages, tubes, grooves and holes, through which the oil is pumped, under pressure and in large volume, to the bearings and surfaces to be lubricated and cooled.
|
|
|
| Distributor |
|
A mechanically driven device on an engine that is responsible for electrically firing the spark plug at a predetermined point of the piston stroke.
|
|
|
| Distributorless Ignition System (DIS) |
|
An ignition system that does not use a distributor to route high voltage to the spark plugs. The high voltage plug wire runs directly from the ignition coil to the spark plug. Some DIS systems have one coil for every two spark plugs (a shared system), whi
|
|
|
| Dog Tracking |
|
An ignition system that does not use a distributor to route high voltage to the spark plugs. The high voltage plug wire runs directly from the ignition coil to the spark plug. Some DIS systems have one coil for every two spark plugs (a shared system), whi
|
|
|
| DOT 3 |
|
A brake fluid with a glycol base, clear or light amber in color. Good for use in most domestic cars and light trucks.
|
|
|
| DOT 4 |
|
A brake fluid with a borate ester base, clear or light amber in color. Good for use in many European cars and for vehicles used in high-altitude, towing, or high-speed braking situations.
|
|
|
| DOT 5 |
|
A brake fluid usually made with a silicone base, violet in color. Good for use in heavy-brake applications, and for weekend, antique, or collector cars that are rarely driven.
|
|
|
| DOT 5.1 |
|
A brake fluid with borate ester base, clear or light amber in color. Good for use in severe-duty vehicles such as fleets, towing and delivery trucks and racecars.
|
|
|
| Dowel Pin |
|
A pin, inserted in mating holes in two different pads allowing those pads to maintain a fixed relationship.
|
|
|
| Drive Shaft |
|
The propeller shaft that transmits engine torque to the differential, or from the differential to the drive wheels. In front-wheel drive vehicles, the two drive shafts are often referred to as "half shafts."
|
|
|
| Drive Train |
|
All the moving components of the car as a whole including the engine, clutch, transmission, driveshaft, differential, axles and wheels.
|
|
|
| Drum Brake |
|
A braking system which consists of two brake shoes and one or two wheel cylinders, mounted on a fixed backing plate, and a brake drum, mounted on an axle, which revolves around the assembly.
|
|
|
| Dual Circuit Brakes |
|
Safety design incorporated on modern cars which ensures there are two largely independent hydraulic brake circuits. Some dual circuit systems are more sophisticated than others.
|
|
|
| Duo-Servo Drum Brake |
|
A self-energizing drum brake that has servo action when traveling forwards or backwards.
|
|
|
| Duty Solenoid |
|
On a feedback carburetor, a solenoid that cycles many times per second to control a metering rod, hence the air/fuel mixture. The "on time" (duty cycle) of the solenoid determines the air/fuel ratio.
|
|
|
| Dwell |
|
The rate, measured in degrees of shaft rotation, at which an electrical circuit cycles on and off.
|
|
|
| Dynamic Balance |
|
Wheel balance that results from the equal distribution of weight on both faces or sides of a wheel. Achieving dynamic balance requires spinning the wheel to identify the heavy spots on each side. A wheel that lacks dynamic balance will shimmy back-and-for
|
|
|
| Dynamic Wheel Loading |
|
The amount of weight being forced onto each road wheel as a result of the car pitching, rolling or squatting during acceleration, braking or cornering.
|
|
|
| Dynamometer |
|
A machine that's used to measure the horsepower output of an engine. A chassis dyno has large rollers upon which the drive wheels are placed. The vehicle is run up to a certain speed and put under load so the amount of power that's being delivered to the
|
|
|
 |
|
 |
