Skip the auto shop - Our mechanics make house calls

Q: Whining Sound from alternator when cold start

asked by on

My Cherokee recently started making a whining sound when I start it up and when I accelerate (I'm not able to post the video I have of it). It mostly happens when it's cold outside. Once the engine warms up it stops. Everything handles as normal, haven't noticed any difference besides the sound. Recently got a new battery and starter. I replaced the serpentine belt and tension pulley about 2 years ago. The belt and all the pulleys look good to me.

The sound is clearly coming from the alternator. I've had alternators go out before, but never heard a sound like this. Is it going bad? I have the V6 so with all the extra space in the engine compartment it would be a very easy fix. But if I don't have to drop the money I dont' want too.

Ideas? Do I need a new alternator?

Here's the sound: https://www.youtube.com/watch?v=a-C64SgyvLo

My car has 155000 miles.
My car has an automatic transmission.

The whining sound is a sign that the bearings in the alternator are going out. This is a problem that will only get worse as time goes on. Eventually, you may also notice the alternator may begin to smoke a bit due to the friction caused by the worn out bearings. I would suggest having a professional from YourMechanic come to your location to diagnose and replace your alternator.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Whining Sound from alternator when cold start

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Car is dead

Hello, and thank you for writing in. The battery is simply used when starting the vehicle, and to complete the charging circuit. The alternator powers the vehicle while it is operating. If there are no electrical components working, then the...

Q: Won't start unless I wiggled the solenoid harness. Extreme break pressing or shifting through gears several times.

There is a ground or broken wire issue in your vehicle causing the engine to not start. Check the harness to the solenoid and see if there is a loose wire or a broken wire. If the wiring is good,...

Q: Engine turned off but inside of car still on, now engine won't turn back on.

Hi there. The symptoms you're describing with your boyfriend's 2002 Grand Cherokee appear to be related to a broken or worn out ignition switch or relay. The ignition switch on the inside of the steering column is attached to multiple...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.