Air-conditioning noises can indicate proper operation as well as an indication there's a problem developing or present. asked to listen to a certain noise the air conditioning system is making and provide feedback about what it means. In this article we'll discuss both sides of the subject. This will include normal noises you should hear from the system when it's working properly, but first we'll tackle the bad sounds that should be investigated further. Most people are interested in the noises their air conditioning system shouldn't be making, so we will address those first. are perhaps the most common complaint from drivers. In this situation the serpentine belt is often the culprit. These belt noises can sound like a major problem and are sometimes mistaken for bearing failure. It's tempting, but not recommended to use belt dressing for diagnosis, because it contains oils that can damage the rubber. Instead use a high output spray bottle of water and carefully

spray the belt to see if the noise disappears. If it stops squealing when wet this is an indication it needs further inspection. A worn or stretched out serpentine belt along with a malfunctioning tensioner are some of the problems that can develop with an air-conditioning drive belt. However, poor quality parts can make a racket all on their own. I prefer to use Continental Elite or Goodyear Gatorback engine belts with quite technology when replacing parts. Bad compressor pulley bearings can also make noise. In this situation it increases when the compressor clutch is engaged. Determining the difference between belt and compressor problems can be tricky. If the belt is old you might consider replacing it for maintenance reasons and see if it solves the noise problem. If you need more information on this subject I have posted some diagnostic information and several popular drive belt diagrams on my other site. When in doubt seek professional diagnosis.

When we talk about AC compressor noises we're discussing sounds it can make when the unit is engaged. diy ac repair helpIf the Freon has leaked out, it won't turn on, so nothing is moving inside. heating cooling unit reviewsIn this scenario people might try adding refrigerant on their own. new ac units for saleThen when the unit kicks on they could hear a noise. A buzzing noise from the compressor when the air-conditioning clutch is engaged is a sign of an overcharged system. In this situation the buzzing sound is caused by liquid refrigerant entering the compressor intake port. Of course, this problem is most common after an air conditioning service when too much Freon has been added. When this is the case it needs to be corrected as soon as possible, because it can cause internal damage.

Replacing a car air-conditioning compressor is expensive and harder than it looks. Also note the AC will not cool properly when it's overcharged. Next up is knocking or clicking sounds while the air conditioner is running. caused by loose mounting bolts that secure individual air-conditioningThis isn't as common as the above conditions, but I have found this issue more then once. You can literally stand back and see the loose component shake and move when the engine is running. Nevertheless, this may actually be the best case scenario for car owners when it comes toTightening a few bolts and adding some thread locking compound will solve the problem for good. Many times a friend or customer will ask me to come listen to a strange hissing sound when the automobile is turned off. Naturally, this is after running the system for a while on a hot summer day. Although this hissing noise, sounds like a bad noise, it's actually a good air conditioning noise. The hissing sound is caused by equalizing pressure.

AC system is running there is a high side and a low side that's divided by either an expansion valve or an orifice tube. sides of the system are necessary for proper operation. When the vehicle is turned off or the air-conditioning compressor clutch is disengaged the system will equalize the pressure. sound is the Freon from the high pressure side slowly feeding into the low pressure side and this is completely normal. Another good air conditioning noise is the roar of theWhen the AC is running the condenser fan will pull additional air through the radiator and the condenser, removing heat from the freon gas and returning it to a liquid state. can cause additional noise that's not present when the systemOften this additional noise is sensed as a problem by the driver as it can be quite loud. You can check with your auto mechanic to make sure that this is a normal condition. Favorite or show friends this air conditioning noises page.

I recommend that you take a few minutes to learn more about your air conditioning system from my free articles available on the you fixThis next link will take you to the beginning page for this section from this page about air-conditioning noises. The homepage is a good place to find out what's covered on the website. Learn about how to get your DIY auto repair questions answered.click here to skip this sponsored messageclick here to skip this sponsored message I have many different AC adapters and power supplies for a variety of devices, ranging from small 5V/1A USB chargers to laptop power adapters and desktop PSUs. However, I often hear a whining noise from some of these power supplies. This happens most often when they are not connected to a device or otherwise in use, and stop making noise when I connect a load to it such as by plugging in a device that is not fully charged. Why do some AC adapters and power supplies make this whining noise? Why do some not make this noise?

Is there anything I can do to suppress it? power-supply noise charger community-faq-proposed Most power conversion devices contains coils, such as transformers or inductors. These components use electromagnetism to convert AC mains power to low-voltage DC power. The varying magnetic fields generated by these components can cause them to physically vibrate at high frequency, resulting in a high-pitched noise. Most modern AC adapters are switched-mode power supplies. The internal switching frequency of an SMPS is typically low when unloaded and increases with load up to a certain point depending on the design. The no-load frequency is often low enough to be within the human hearing range. In addition, in low or no-load situations, the PWM used to regulate voltage at the inverter stage will be at a low duty cycle creating a "spikey" output profile which is more prone to causing vibration in coils, and the transformer itself will tend to vibrate as well (see Daniel R Hick's answer below for more details).

Together, these can lead to audible noise especially in cheaper units which fail to suppress this noise. Under load, a properly functioning SMPS should operate at a frequency well above the human hearing range, typically 50 kHz or higher (although some older designs operate at 33 kHz). However, the same noise can occur under load with a poorly designed or defective power supply as the coils may vibrate under electrical stress at a subharmonic frequency. Coils used as inductors or transformers in other electronic devices, including those on motherboards, graphics cards, or other computer components, can also vibrate during operation. As such, a defective device can generate audible coil whine during operation. This is why you sometimes see weird gobs of glue on coils inside electronic devices. The glue helps reduce the vibration and noise the coils generate during normal operation. It is entirely possible for users to apply glue onto coils using a glue gun to suppress coil whine, and people have successfully done so on their computer parts.

However, you generally can't do this easily on small wall chargers of the sort you mentioned without risking damage to the charger or exposure to potentially dangerous voltages. Ultimately, a whining noise isn't necessarily a sign of trouble in cheaper wall chargers when little or no power is being drawn from them. However, a computer PSU or laptop charger that generates coil noise especially when under load may be defective and you may want to consider replacing it. More information on coil noise can be found in this Wikipedia article. A "switching" power supply (like virtually all modern computer power supplies) works by "rectifying" the incoming 120V 60Hz (in the US) AC power into DC (at around 170 volts), "filtering" with capacitors, then using a semiconductor circuit to "chop" the DC voltage around 1000 times a second to turn it back into crude AC. (What's referred to as a "square wave", vs the "sine wave" of ordinary AC.) This "chopped" voltage then runs through a transformer to produce the desired output voltages.

The outputs are again rectified to DC and filtered, to produce the desired voltages for the computer. With this scheme, basic voltage regulation is performed by adjusting the "duty cycle" of the chopped voltage. When the power supply is lightly loaded the circuitry doesn't produce a nice symmetrical "square wave" but instead a series of narrow spikes, and that "spikey" waveform is more likely to produce annoying audible noise in the transformers and other components and is also more likely to produce "electrical noise" that you would, eg, hear in a nearby radio. Additionally, when a power supply is lightly loaded more of the magnetic field inside a transformer escapes to the case of the transformer and to surrounding components (since less is captured by the "secondary" coil of the transformer), and this "escaping" magnetic field is more apt to cause noise. The transformers are created in part by gluing plates of metal together. The AC fields causes back and forth forces in the metal plates.

As the transformer ages the plates begin to separate and allows for movement on the plates which vibrate causing the humming sound you hear. Is there anything I can do to suppress it? As they've already told you, glue, because glue adds damping to the vibrating coil, then the coil's stationary response gets smaller as well as the noise produced glue adds constraints to the coil, then the coil's (mechanical) fundamental frequency increases above your hearing capability. Another solution that wasn't mentioned (disclaimer: I haven't read ALL the comments...), and an environmental sound one! consists in unplugging the adapter (that's what I do all the time with the charger for my Nokia cellphone!) I came to this page as I bought a new Craftsman C3 19.2 V Li-ion battery / charger which started making that whining noise as I plugged in. I came up to look for some answer, while reading it, I realized I had one or two wireless charging toothbrushes (Philips Sonicare and an Oral B) next to it.