Skip the auto shop - Our mechanics make house calls

Q: My car is making a squealing sound when it cranks and when I turn on the A/C

asked by on

Hi, I have a 2009 Hyundai Elantra and my car squeals really loud when I first crank up, the car does settles after a couple minutes. If I try to drive while the car is squealing, it gets even louder. Also, my car squeals when I turn on the A/C. Do you know what could possibly be my problem? I have recently gotten a new alternator belt. Also, I think that possibly a bolt or something could be missing or loose, based on what one mechanic told me.

My car has 100000 miles.
My car has an automatic transmission.

A: Hi, thanks for writing in. What you’re desc...

Hi, thanks for writing in. What you’re describing sounds a lot like an AC belt that is loose or the serpentine belt on your alternator loose (or a combination of both). A common mistake that some mechanics make is not properly tightening the alternator after replacing the belts. The fact that the previous mechanic indicated that there may be a bolt missing also raises a red flag to me that the alternator might be a problem.

However, you mentioned also that the car squeals when you turn on the AC and that it gets louder as you drive. When a belt is loose it creates a harmonic squeal, and as the belt moves faster (when you accelerate) it progressively gets worse.

I think the best thing you can do is to find a another mechanic that can fully inspect your alternator and AC belts, replace any lost nuts or bolts on your current alternator, and get rid of that annoying squealing sound. A certified technician from YourMechanic can come to your home or office to inspect you AC squeal and let you know exactly what needs to be done.

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!

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: How do I read the engine temperature gauge?

The engine temperature gauge is located on the instrument panel, and displays the temperature of your engine coolant. When the gauge approaches the H (High), you should stop your car as soon as possible to let the engine cool down....

Q: I need help replacing stock headlights with Halo LED Projector HID headlights.

This is more of an aftermarket-type of repair. You are right about needing 2 more ballasts, and I recommend you get them from the same manufacturer as the kit you have. For this type of modification, consider visiting a local...

Q: Wheel Bearings

This may be a sign of failing or worn out wheel bearings. A wheel bearing will usually fail due to pitting or small damage on the surface of the rollers or the bearing race. Both the surface of the rollers...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...