Car dictionary: automotive terms
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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. |
• Anti-lock Braking System (ABS)
• Alternator
• Automatic Transmission
• Ball joint
• What is Bank 1 or Bank 2?
• Battery
• Check Engine light
• Control arm
• CV joint
• DOHC engine
• Drive belt
• EGR System
• Head Gasket
• Idle Air Control (IAC) valve
• Mass Air Flow sensor (MAF)
• OHC engine
• OHV engine
• Overdrive
• Oxygen sensor
• Pushrod engine
• Serpentine belt
• SOHC
• Stabilizer bar link
• Starter
• Starting system
• Thermostat
• Timing belt
• Twin Cam
• Water pump
• Wheel alignment
• Wheel bearing
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. |
Ball Joint
What is Bank 1 or Bank 2
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. |
Battery
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
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. |
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 Belt (Serpentine Belt)
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. Drive belt problemsA 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. Drive belt replacementA 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. |
EGR system
Ford EGR vacuum-operated valve |
Mazda electric EGR valve |
The EGR system (Exhaust Gas Recirculation system) is designed to reduce emissions. To be precise, it lowers the amount of nitrogen oxides (NOx) in the exhaust gases.
Nitrogen oxides are formed at very high combustion temperatures. The EGR system diverts part of the exhaust gases back into the intake manifold, diluting the air/fuel mixture. As the exhaust gases are not combustible, mixing them with the air/fuel charge helps to reduce the combustion temperature and consequently lower the amount of NOx in the exhaust gases.
The EGR flow is controlled by the engine computer which opens or closes the EGR valve depending on the operating conditions. Typically the EGR flow is at its maximum during steady cruising.
Some cars have a vacuum-operated EGR valve (upper photo), others have an electrically controlled EGR valve (lower photo). Some newer cars don't have the EGR system at all, as using a Variable Valve Timing system eliminates the need for an Exhaust Gas Recirculation (EGR) system.
The engine computer (PCM) constantly monitors the operation of the EGR system. If the PCM detects a problem, it turns the Check Engine light on and stores one of the EGR-related OBDII trouble codes (from P0400 to P0409). For example, the code P0401 - Exhaust Gas Recirculation (EGR) Insufficient Flow was a common problem in some Ford vehicles; often this was caused by a bad DPFE sensor. Some Honda and Acura vehicles also had a common problem with clogged EGR port causing the Check Engine light.
Read more about EGR-related OBDII trouble codes.
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