If you hear unusual noise at the air conditioning system, these compressor sounds could indicate the need for a simple service and adjustment requirement. But air conditioner compressor noises might also mean that you face an upcoming costly repair involving replacement of the compressor itself. You should have the system checked promptly by a San Diego air conditioning pro. The following is a list of air conditioning compressor noises and what they may mean about the operation, condition, and remaining life of the cooling system equipment.

Banging or Clanking air conditioner / heat pump compressor noises, at least the costly ones, are usually due to a loose connecting rod, piston pin, crankshaft, or other internal part. Since compressors on most modern commercial and residential air conditioning systems are a sealed unit, the only repair is to replace this (costly) part. A similar clanking or banging sound can be caused by loose internal mounts.
Bubbling, hissing, refrigerant leaks: a catastrophic refrigerant leak on the air conditioner or heat pump high pressure side will make a loud hissing sound – but that sound won’t continue for any longer than to dump the refrigerant into the atmosphere (something prohibited).But a more subtle refrigerant leak that results in low refrigerant can result in refrigerant gas bubbles traveling around in the liquid refrigerant line. You might hear bubbling sounds at the refrigerant piping or see bubbles in the sight glass if your system has one.
Buzzing noises at the outside fan motor: sounds like a failing motor; check first for loose wiring, arcing connections, arcing or burning at the fan contactor relay switch.
Chattering or rattling noise in the A/C or heat pump compressor motor at start-up on some models of HVACR equipment whose compressor uses a compressor crankcase heater element if the equipment is started-up before allowing 24-hours of power-on time first.Example from Carrier: “On 24ANA7 models, starting the compressor without a minimum of 12 hours of crankcase heat prior to initial start–up may result in a compressor chattering noise and possible damage to the compressor.“
Clanking or rattling air conditioner or heat pump compressor: the compressor motor mounts have failed and the motor is thrashing around inside the hermetically-sealed compressor motor can. It may look normal from outside, but the clanking sound is coming from inside the sealed unit. The compressor should be replaced.
Clicking, rumbling, ticking, rattling, clang and clunk at startup: loose hardware: Air conditioner compressor noise could be due simply to loose hardware such as a loose shipping bolt, tubing, or a broken spring. Does the noise sound like a metallic rattle?A visual inspection for loose hardware may help diagnose this condition. Sometimes a shipping bolt may have been left in the unit and could be the source of a rattle. Loose refrigerant tubing or a bend in tubing that carries it too close to the air conditioner frame or case can lead to rattling that is easily corrected with a careful bend.Warning: Beware of both the chance of electrical shock and of injury from moving compressor parts like the cooling fan which can easily chop off a finger. Homeowners should not attempt to open, disassemble, or repair an air conditioner compressor as special training and safety procedures are needed to avoid injury.

For additional information regarding noises with you air conditioning system or general air conditioning repairs in San Diego contact United Plumbing Heating Air & Electric.