Car dictionary: automotive terms

Do you want to know what your mechanic or a service adviser is talking about? Here we list some car-related terms with illustrations and explanations. If you cannot find what you are looking for or want to know about something else, let us know. We will add more information.

Volkswagen 2.0 TSI engine alternator

An alternator supplies an electric power for the vehicle's electric systems and charges the battery when the engine is running. An alternator is rotated by a drive belt connected to the engine crankshaft.
If the alternator fails, the warning light or "CHARGE" icon comes on on the instrument panel.
Alternator problems are common. If the alternator fails it needs to be rebuilt or replaced.

Ball joint

A ball joint is a part of a vehicle front suspension. Most cars have one or two ball joints at each front wheel. A ball joint is lubricated inside and sealed with a rubber boot. When a ball joint becomes bad, a vehicle could be unsafe to drive; a ball joint, when badly worn, can separate causing the vehicle to lose control unexpectedly.
One of the possible indication of a bad ball joint could be a knocking noise coming from the front end, particularly while driving over bumps or making sharp turns. If you suspect your vehicle has a bad ball joint or any other suspension component, have your car inspected as soon as you can, it can be unsafe to drive. It's recommended to check the vehicle's chassis in a garage on a lift at least once a year to discover potential problems with suspension, brakes and other components.

Typically, the engine bank that contains cylinder 1 is called Bank 1

The engine Bank is the group of cylinders aligned together. The term Bank 1 usually refers to the bank of the engine that contains the cylinder number 1.
In an in-line 4-cylinder engine all 4 cylinders are grouped together, so there is only one bank (Bank 1).
A V6 or V8 engine has two banks (see the diagram), each with three or four cylinders respectively. Usually, in a V6 or V8 engine, the bank that contains the cylinder 1 is called Bank 1 and the opposite bank is called Bank 2.

The battery provides electric power to start the car. I get many questions like "My car doesn't start, it only makes a click-click noise when I'm trying to start it" - this is most likely the result of the battery having decided to quit. Unfortunately, usually it happens unexpectedly - the battery just stops working one day. If your vehicle doesn't start and you suspect the battery, there is a simple way to check it. Try switching the wipers on - if they move very slowly, a lot slower than usual (too low voltage) the battery is probably discharged or dead.

Control arm

Lower control arm. Ford F150

A control arm is a part of the front suspension. Some cars have one control control arm on each side; other vehicles, including many trucks have two (upper and lower) control arms on each side of the front suspension. The internal side of the control arm is connected to a vehicle's body or a frame through the rubber bushings (control arm bushings). An outer end of the control arm holds a ball joint. A ball joint could be bolted to or pressed into the control arm. Sometimes, a ball joint is an integral part of the control arm and if it goes bad the whole control arm must be replaced.

One of the common problems with control arms is when the control arm bushings wear out. Sometimes the bushing can be replaced separately. Typically they have to be pressed into the control arm.
In some cars if the control arm bushings go bad, the whole control arm has to be replaced as it comes as an assembly.
After the control arm bushings or the whole control arm is replaced, the wheel alignment must be performed on most cars.

CV joint.

All front-wheel drive cars as well as some four-wheel drive vehicles have Constant Velocity joints or CV joints on both ends of the front drive shafts; the inner CV joints connect the drive shafts to the transmission and the outer CV joints connect the drive wheels to the drive shafts. The CV joints are needed to transfer the torque at a constant speed to the steered wheels as well as to accommodate up and down motion of the suspension. A CV joint is packed with a grease and sealed tight by a rubber or plastic boot. A CV joint doesn't need any maintenance and can last very long, as long as the protective CV joint boot is not damaged. Read full article: CV joint

Drive (serpentine) belt. BMW engine. Click for larger image.

Self-adjusting drive belt tensioner. Ford engine.

Water pump driven by a drive belt.

Badly worn drive belt. You can see cracks and missing chunks. Click for larger image.

A drive belt is used to drive accessories installed on your car engine, such as an alternator, water pump, power steering pump, air conditioner compressor, etc. Sometimes a drive belt could also be called a "serpentine belt" or "accessories belt". Some cars have a single drive belt running all the accessories, others may have two or more drive belts.

Drive belt tensioner

A belt tensioner keeps the drive belt under proper tension. In some older cars, a belt tensioner had to be manually tightened from time to time. If not tightened in time, the belt would get loose and start slipping, making a loud whistling or squeaking noise. Commonly you would hear this noise when the car is just started cold in the morning or when turning the steering wheel left or right to the limit.
Most of the newer cars have a drive belt with a self-adjusting tensioner that maintains proper belt tension automatically.

Drive belt problems

A drive belt is made from very flexible and durable material, but it still wears over time. Improper tension, excessive heat and the engine oil leaking onto the belt can cause the belt to wear faster. A worn out belt may cause squeaking or whistling noise and a badly worn out belt can break.

What happens if the drive belt breaks

If the drive belt breaks, all the accessories driven by the belt will stop working leaving you waiting for a tow truck. This happened to me once in the early days and I spent few hours on the side of the road waiting for towing. In many cars a serpentine belt drives a water pump and power steering pump. If the drive belt breaks, the engine will overheat as the water pump will stop circulating the coolant into the radiator to cool it down. A car will also lose a steering assist and the steering will become very hard. For this reason it's important not to overlook a drive belt during a regular maintenance and replace it at recommended intervals.
A drive belt also needs to be replaced if it shows any damage, such as cracks, tears, cuts, etc. (lower photo). It's also a good idea to replace a drive belt before a long road trip if it's been a while since it was changed the last time. Read more: Car checklist before a long trip.

Drive belt replacement

A drive belt is not very expensive part and usually doesn't cost much to replace. Roughly, a drive belt replacement in a garage could cost anywhere from $90 to $180. On most cars it's a fairly simple job that typically takes no more than 30-40 minutes.