Alternator
The engine-driven generator that makes electricity for the car and keeps the battery charged.
In plain English
The alternator is a small generator bolted to the engine and spun by a rubber belt. While the engine runs, it makes the electricity that powers the lights, the electronics, and the engine's own ignition and fuel systems. It also refills the battery, which is mainly there to start the car. Without a working alternator, the car runs on whatever charge is left in the battery.
Why it's on your estimate
Alternators wear out inside, and a shop will usually recommend a new one after a charging system test shows it is not putting out enough power. Common signs are a battery warning light on the dash, headlights that dim or flicker, a battery that keeps going dead, slow power windows or other weak accessories, and a whining or growling noise from the engine area.
How urgent is it?
Fix soon
The car will often still drive for a while, but once the battery runs down the engine can stall and may not restart, which can leave you stranded. If the battery light is on while you are driving, or you notice a burning smell, get it checked right away.
Questions to ask the shop
- Did you test the charging system, and what did the alternator and the battery each show?
- Could the problem be the belt, a loose connection, or the battery rather than the alternator itself?
- Is the replacement part new or remanufactured?
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