Water Pump

A device within a vehicle used to circulate coolant across its cooling system. This cooling process is essential to ongoing engine functionality.

Water Pump Weep Hole

A small hole equipped on a water pump below the exposed end of the pump shaft. It is used to allow fluid to drain from the water pump and protect the strength and integrity of bearings.


A measurement of the total power amount an amplifier can produce within a vehicle. For example, an average 12V car battery can produce around 500 watts of power. This term may also refer to the total power output a speaker can handle before suffering damage or malfunction.

Weather Stripping

Rubber linings installed around doors, hatches, and other access points out of the vehicle. These devices prevent leakage into a vehicle during inclement weather such as rain or sleet.

Well to Wheel

Refer to “Environmental Impact” for more information.

Wheel Alignment

Repositioning of various wheel components to improve the balance, equilibrium, and overall performance of a vehicle. Adjustment levels are usually predetermined by a vehicle’s manufacturer or wheel/tire producers for aftermarket parts. Specifications include adjustments to the camber, ride height, toe, and canister.

Wheel Bearing

Components within a wheel system which accommodate smooth rotation between a spindle and the wheel hub. Properly lubricated wheel bearings are essential for ideal wheel movement.

Wheel Covers

Decorative or protective disc covers equipped onto wheel installations of a vehicle. The covers obscure the steel wheel components and usually the lug nuts as well. A wide range of styles are available for covers.

Wheel Cylinders, Rear

Used in drum brakes, small hydraulic cylinders which are equipped between brake shoes. They are located in each wheel and are used to apply force onto the brake shoes, making contact with the drum to stop the vehicle with the resulting friction.

Wheel Diameter

Total diameter measurement across a vehicle’s wheel. In most wheel descriptions, it is measured in inches.

Wheel Locks

Specialized lug nuts equipped on wheels which act as a theft deterrent. Wheel removal can only be accomplished using a specific wrench or key. Normal tools will not loosen these lug nuts. They can be installed in locations where there is a higher risk for vehicle theft.

Wheel Lug Nuts and Bolts

Large, rounded nuts or bolts which are used to securely hold a wheel onto the hub of the vehicle chassis. Improper securing with lug nuts can cause a wheel to fall off a vehicle.

Wheel Offset

The measurement which helps to locate a wheel and tire assembly relative to its suspension. It is determined by measuring the distance between the mounting surface of a hub and the centerline of the rim. A positive offset means that the hub mounting surface is located on the outer (street) side of the rim’s centerline. Zero offset means the mounting surface is directly centered with the rim and contains no offset. Negative offset occurs when the hub mounting surface is located on the inner side of the rim’s centerline. A negative offset may cause adverse driving effects such as added stress to the suspension and kickback from the steering wheel.

Wheel Specs

The specific dimensions that outline all the size elements of a vehicle’s wheels. This could include width, diameter, and multiple other factors.

Wheel Speed Sensor Wiring

Electrical wiring connections which utilize sensors to detect individual wheel speeds and report them to a vehicle-controlled computer system. The system can identify any imbalance among the wheel speeds and automatically adjust the brakes to even them out. These adjustments are used to enable ongoing smooth vehicle operation while preventing the wheels from experiencing a lock up.

Wheel Width

The measurement of the wheel between both beads. This determines the acceptable sizes for mounting wheels onto vehicles.


Measurement of the total distance between the center of a vehicle’s rear axle to the center of its front axle. This measurement can determine the precise point of equilibrium between both axles.

Wholesale Value

A vehicle pricing which reflects the amount paid by dealers when purchased from lenders or other dealers. Wholesale purchases usually occur during vehicle auctions. Dealers then mark up prices when selling vehicles to the public to cover overhead and administrative costs.

Wideband Oxygen Sensor

An oxygen sensor equipped in a vehicle which allows its engine control unit to rapidly adjust the air and fuel ratio within the combustion system. The wideband design allows for a greater level of precision for these adjustments compared with older style oxygen sensors. Dynamic adjustments of the air/fuel ratio can improve a vehicle’s performance, reduce its output of harmful pollutants in emissions, and improve the fuel economy during operation.


A measurement spanning across the wide side of a vehicle – taken at the very widest point.

Window Control

The type of window system equipped in a vehicle which control how they are operated. Common systems include manual control, automatic, one-touch automatic, and remote control. Higher functioning controls such as remote or one-touch may be equipped as an additional feature from the manufacturer or as an aftermarket installation.

Window Sticker

Refer to “Monroney Sticker” for more information.

Wireless Data Link

A communication method which transfers data wirelessly between a vehicle’s systems and another device such as a mobile phone. These links are usually established using Bluetooth or Wi-Fi technology.

Wiring Harness

Groupings of wires and connectors which are used to move electricity throughout the various systems within a vehicle. The harnesses keep the wires organized and easier to locate for service or replacement.