What sound does a bad AC compressor make?

A/C compressor

A/C operation, normal noises.

Normal noises include the sounds of A/C compressor clutch engagement, the blower motor, moving blend air and mode doors, and pressure equalization after vehicle is shut down.

Noises that could indicate the need for a/c compressor service or replacement include:

  1. Growling noise with compressor disengaged
  2. Whistling noise
  3. Grinding noise
  4. Squealing noise
  5. Rattling noise
  6. Growling noise with compressor engaged
  7. Banging noise
  8. Knocking noise

Why is my AC making a weird noise?

Banging noise: If liquid refrigerant enters the compressor, a thumping, banging noise will result.

Knocking noise: Heavy knocking compressor noises come from refrigerant system blockage, incorrect pressures, or internal damage.

Growling noise with compressor disengaged: A worn compressor pulley bearing or clutch bearing will cause a growling noise.

Growling noise with the compressor engaged: A/C compressor internal bearings damage.

Squealing noise: A loose, dry, or worn A/C compressor belt will cause squealing noise. This noise will be worse during acceleration.

Worn or dry blower motor bearings may cause a squealing noise when the blower motor is running

Rattling noise: A loose or worn clutch hub or loose compressor mountings bolt will also cause rattling noise from the compressor.

Knocking noises: This type of noise from the compressor usually indicates internal damage, especially on piston-type compressors. Always check the compressor mounting and brackets before condemning the compressor for noise.

A loose mounting can cause knocking noises from the compressor area that may be mistaken for internal compressor noise.

Grinding noise: When car accessories pulley bearings are failing, they can make this kind of noise.

What are the Symptoms of a Bad or Failing Ambient Temperature Sensor?

Diagnosing a bad or failing Ambient Temperature Sensor.

  1. The air conditioning  “AUTO MODE “ won’t  work
  2. Inconsistent cooling or not cooling at all.
  3. A/C compressor inoperative
  4. Incorrect reading on temperature gauge. Usually a default negative temperature.

Thermistor.

The most common variable resistor is a thermistor.Thermistors change resistance based on temperature changes. There are two different styles of thermistor: NTC (Negative Temperature Coefficient) and PTC (Positive Temperature Coefficient).The difference is in how they react to temperature changes.

As temperature rise:

-PTC thermistor-resistance increases

-NTC Thermistor-resistance decreases

The NTC thermistor is more common than the PTC thermistor.

Here are some examples of thermistor in automotive circuits:

  • Engine temperature sensor
  • Evaporator temperature sensor
  • Ambient temperature sensors-In-car and outside sensors
  • A/C High Side Refrigerant Temperature Sensors
  • A/C Low Side Refrigerant Temperature Sensors
  • Sun Load Sensors (Not all sun load sensors are thermistor some are photoresistors.A photoresistor measures the amount of light hitting it .As the light intensity increases , sensor resistance decreases. That’s the why a photo resistor works so well as a sun load sensor. Some manufacturers use a photodiode. A photodiode works in a manner similar to the photoresistor.
What does the ambient temperature sensor do?

It prevents the compressor from engaging when ambient temperatures get too low. The oil that resides inside of a compressor can get very cold during the winter months. If the compressor’s clutch is energized while the oil is cold and thick, improper compressor-lubrication would result.

Where the ambient temperature sensor is usually mounted?

Location:

Mounted to the radiator support, in front of the condenser where it can sense outside temperatures without being affected by engine heat.

How does ambient temp sensor work?

A lot of air conditioning systems are supposed to run when you turn the defroster on, to help remove moisture from the air. But when outside temperatures are very low refrigerant oils won’t flow and lubricate the system properly.

The ambient temperature sensor prevents the compressor from running when it’s too cold for the system to work safely. These switches open when the temperature drops below a preset temperature,usually below 32° F

How do you diagnose an air conditioner

A/C system check up in Miami-Dade County

Air Flow

Car ac blower motor replacement service & cost

No air flow

  1. Inspect blower motor
  2. Inspect blower motor resistor
  3. Inspect fuse
  4. Inspect A/C climate control
  5. Inspect connectors
  6. Inspect harness
  7. Inspect hvac box for

Cooling

No cooling

Automotive ac system.Head control set.Hvac electrical and electronic

  1. Inspect A/C switch
  2. Check refrigerant level
  3. Inspect clutch relay
  4. Inspect PCM/BCM/ECM
  5. Inspect A/C pressure switch
  6. Inspect compressor clutch coil
  7. Inspect compressor clutch
  8. Inspect compressor clutch air gap
  9. Inspect condenser
  10. Inspect condenser fan
  11. Inspect radiator fan
  12. Inspect evaporator temperature control devices
  13. Inspect temperature sensors control devices
  14. Inspect climate control
  15. Inspect in cabin temperature sensors
  16. Inspect sun load sensors
  17. Inspect power steering pressure sensor

Bad Smell

Leaking evaporator core on site replacement.
2000 Toyota 4runner sr5 on site evaporator replacement.

  1. Check cabin air filter
  2. Check evaporator core
  3. Check hvac box drain tube
  4. Check re-circulation air door /actuator
  5. Check hvac box seals

Noise

Clicking noiseA/C compressor relay

  1. Check A/C clutch
  2. Inspect A/C clutch relay
  3. Inspect cycling switch
  4. Inspect refrigerant level
  5. Inspect evaporator temperature sensor
Squealing

Worn serpentine belts & car ac compressor output.
Serpentine belt type of damage and the negative impact they have on the air conditioning system.

  1. Check drive belt
  2. Check belt tensioner
  3. Check compressor for seizing
Grinding

A/C compressor

  1. Check compressor
  2. Check compressor clutch
Other helpful tips

Replace the receiver driver with every A/C service.

Replace cabin air filter annually

Ensure that service valve caps are in place at every A/C service.

Does engine coolant affect ac performance?

High coolant temperature affects A/C performance.

The engine cooling system has an indirect influence on the performance of the A/C system. High under hood temperatures can be the cause of poor A/C output. 

Always verify correct operation of:

  • Engine coolant level and condition
  • Low coolant will cause high under hood temperatures
  • Does the cooling system need flushing?
  • Has the vehicle followed the manufacturer’s service intervals for flushing?
  • Does it have the correct coolant in it?

  • Thermostat
  • Has the thermostat ever been replaced?
  • Is it stuck, not closing or opening all the way?

  • Radiator
  • Is the radiator plugged internally or externally?
  • Are there any signs of leaks?

  • Water pump
  • Is the mechanical pump circulating the coolant properly?
  • Are electric pumps working properly?
  • Should it be replaced when servicing the timing belt?
  • Belts,tensioners,and pulleys
  • Check for proper belt tension and verify the belt is not slipping
  • Check tensioner alignment

Why did my car AC stop blowing air ?

My car A/C stop blowing air from the vents.

Common reasons for this to happen:

  • A/C blower motor circuit blown fuse
  • Bad blower motor resistor
  • Blower motor shorted
  • Bad blower motor control switch
  • Poor ground connection
  • Poor blower motor connections

Ram air flowing through the evaporator does not provide enough air flow inside the vehicle for cooling purposes. So, a blower is used to force the air along. An electric motor spins a fan, forcing the air into ducts, which direct it to the particular vent selected by the operator.

If the blower motor gets full voltage, it will run at high speed, but that is not always desirable. Therefore resistors are used to cut the speed down. The fan switch directs the current flow through one or more resistors to achieve the slow and medium speeds.

Why did my car AC suddenly stop working?

The most common causes of broken air conditioning are:

Leaks, compressor issues, electrical / electronic faults.

Compressor and electrical / electronic faults.

Inputs that may affect A/C clutch operation include (but are not limited to):

  1. A/C system pressure
  2. Engine speed
  3. Throttle position
  4. Engine coolant temperature
  5. Intake air temperature
  6. Power steering pressure

If these sensor and switch values are either above or below the programmed operating range, the compressor clutch may not engage

Depending on the vehicle, additional items that may affect compressor operation could include:

  1. A/C mode switch/actuator
  2. Body control module
  3. High and low pressure cut-out switches
  4. Compressor clutch cycling switch
  5. Refrigerant pressure transducer

Refrigerant leaks .

There are two types of refrigerant leaks in the automotive air conditioning system: Active leaks and Passive leaks.

  1. The active refrigerant leak is a continuous leak. It doesn’t matter if the engine or ac system in your car is off or on hot or cold the refrigerant continuously leaks out
  2. The passive refrigerant leak is a type of leak the intermittently occurs. They are really hard to find, because technicians should recreate the same conditions of pressure, temperature or vibration for the leak to happen.

When should I change my AC filter drier?

Receiver-drier location.

The receiver drier is a storage tank for the liquid refrigerant from the condenser. It also contains a bag of desiccant.

The purpose of the desiccant is to absorb any moisture that might enter the system during assembly or service. The receiver drier is often neglected when the air conditioning system is serviced or repaired.Failure to replace it can lead to poor system performance or replacement part failure.

When should I change my AC filter drier?

It is recommended that the receiver drier and /or its desiccant be changed whenever a component is replaced, the system has lost the refrigerant charge, or the system has been open to the atmosphere for any length of time.

AC receiver drier refrigerant flow restriction.

If the receiver-drier outlet is colder than the inlet, this unit is restricted and should be changed to restore efficient and proper system operation.

How much refrigerant does a car need?

What happens when refrigerant is low?

A low refrigerant charge may cause faster than normal clutch cycling without frosting of any components.

 AC system overcharged.

A flooded evaporator would cause elevated low-side pressures and frost to develop on the suction line.

AC system restriction.

A restricted accumulator would likely result in a noticeable temperature drop.

Why does car stall when AC is on?

Why does my car hesitate when AC is on?

A vehicle that is stopped stalls when the steering wheel is turned to full lock only when the air conditioning is on.

The power steering pressure switch signals the computer to increase the engine idle speed during parking-type maneuvers. If the vehicle has a bad power steering pressure switch, the engine could stall at idle when the steering is moved to the full lock position. This is due to increased load on the engine from the power steering pump.