Skip the auto shop - Our mechanics make house calls

Q: Rattling from AC when idling

asked by on

I can hear a rattling noise in the engine compartment when I engage the air conditioner. The air conditioner still works. The rattling sound occurs while idling at stop lights.

A: The rattling may be from the AC compressor ...

The rattling may be from the AC compressor pulley or tensioner for the belt. The tensioner is the most common problem, but the spring may be too weak causing vibrations and rattles. I recommend seeking a mechanic, such as one from YourMechanic, to come and test your vehicle for you. They will be able to diagnose the car noise and replace the belt tensioner if necessary.

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・Save up to 30%

Get a quote

What others are asking

Q: What is wrong with my climate control?

You may be having more than one problem with the A/C system. The control head or A/C control panel is known to have issues and can cause all different problems on this car. The electrical blend door actuators that control...

Q: Evaporator leak

The replacement of the air conditioning evaporator is generally a large task. The evaporator is often located behind the dashboard of the vehicle. Opening the air conditioning system means the receiver/dryer must be replaced as well to ensure proper system...

Q: Air conditioning started blowing hot air

There are many components that allow the air conditioner in your Mercedes to blow ice cold on days when you need it the most, but without a bit more information it is difficult to determine if the A/C compressor is...

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...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...