How can a broken radiator fan on a car cause the air conditioning to stop working properly?

Condenser fan assembly

What is the purpose of the radiator fan assembly ?

The purpose of the fan is to maintain adequate airflow through the radiator and condenser core, especially at low vehicle speeds and when the engine is idling, sitting still. The fan is used to speed up the natural draft through the radiator/condenser or create one if the vehicle isn’t moving.
At high motor vehicle speeds the ram effect through the air is usually sufficient enough to cool the radiator/condenser core so the fan is not required.

Three important things may happen to the refrigerant in The Condenser and we need the radiator fan assembly working at maximum efficiency for The Subcooling process to happen properly:

  1. The hot gas from the compressor is desuperheated from the hot discharge temperature to the condensing temperature. The hot gas from the compressor may be 200 °F or hotter on a hot day on an air-cooled system.Desuperheating is accomplished in the beginning of the coil.
  2. The refrigerant is condensed from a vapor to a liquid. This is latent heat transfer. This is done in the middle of the coil, the only place that the coil temperature will correspond to the head pressure.
  3. The liquid refrigerant temperature may then be lowered below the condensing temperature, or SUBCOOLED.The refrigerant can usually be subcooled to between 10 °F and 20°F below the condensing temperature.

 

Condensers have a relationship to the temperature of the air passing over them. For instance, the refrigerant inside the coil will normally condense at a 30°F higher temperature than the air passing over it.

The four major components that make up the air conditioning system are:

  1. The evaporator
  2. The compressor
  3. The condenser
  4. The refrigerant metering device.

The evaporator absorbs heat into the system. When the refrigerant is boiled at a lower temperature than that of the substance to be cooled, it absorbs heat from the substance.

The compressor: is the heart of the refrigeration system. It pumps heat through the system in the form of heat-laden refrigerant. A compressor can be considered a vapor pump.

 

The condenser: rejects both sensible (measurable) and latent (hidden) heat from the a/c system and delivers subcooled refrigerant to the metering device. This heat can come from what the evaporator has absorbed any heat of compression or mechanical friction generated in the compression stroke, and any heat absorbed by superheating the refrigerant in the suction line before it enters the compressor.

 

The refrigerant Metering Device: The expansion device is one component that divides the high side of the system from the low side (The compressor is the other).It is responsible for metering the correct amount of refrigerant to the evaporator. The evaporator performs best when it is as full of liquid refrigerant as possible with none left in the suction line.

 

AC CONDENSERS

What is a car ac condenser?

The condenser is one of automobile heat exchangers and operates much like the radiator.

The condenser receives the hot gas after it leaves the compressor. The discharge gas from the compressor is a high-pressure, high-temperature, superheated vapor. The temperature of the hot gas from the compressor can be in the 200°F range and will change depending on the surrounding temperatures. Condenser designs have changed over the years, but there have been 3 main types. They are:

Tube and fin condenser

Serpentine tube condenser

Parallel flow condenser

My car AC compressor has blown 15 minutes after a regas/recharge. What could be the cause?

ac hoses and lines on site repair and installation

AC compressor has blown 15 minutes after a regas/recharge.

There is a high chance the system was working with a low refrigerant charge. It was a system performing poorly, but depending on weather conditions the driver wouldn’t notice a problem with the A/C system.

After the system was charged up to full capacity a problem with some restriction on the system or a fan clutch/radiator fan assembly would be more noticeable and would have enough refrigerant running in the system to open the high pressure relief valve and vent some part of the refrigerant.

An overcharged air conditioning system won’t hold more than a couple minutes before the pressure inside the system are high enough to open the relief valve and vent the refrigerant to the atmosphere.

A/C Refrigerant pressure controls

 

High Pressure Relief Valves

The high pressure relief valve (HPRV) is a blow off valve, designed to release refrigerant into the atmosphere if pressures get dangerously high. In an effort to keep refrigerants contained more efficiently, many manufactures have introduced controls designed to prevent pressures from getting high enough for the pressure relief valve to blow off. Single contact pressure switches simply shut the compressor down if pressures get too high.

The dual contact pressure switches have replaced most HPRV to prevent refrigerant venting to the atmosphere.

Fusible Plug

The fusible plug is installed on the top of the receiver/drier to serve as a safety device. The fusible plug has a special solder filled hole. If the condenser ventilation becomes poor and the cooling load becomes excessively large, the pressure in the high-pressure side of the condenser and receiver will become abnormally large and create a danger of bursting the equipment.

When the temperature and pressure in the high-pressure side reaches 427 psi and 200 to 212 °F the fusible plug melts and allows the refrigerant to discharge into the atmosphere thus preventing damage to the equipment (This will add to ozone layer problems)

Dual pressure switch

The dual pressure switch is fitted between the TXV and the receiver-drier. It detects pressure on the high side of the system and switches on the cooling fan(s) to high speeds and turns off the magnetic clutch shutting down the compressor when the pressure is abnormal, thus preventing damage to the system.

Low Side Pressure Relief Valves

Some R-134a systems use a pressure relief valve on the low side of the system. This valve is designed to prevent evaporator damage during system shutdown, when pressures equalize. The higher pressures in R-134a systems could cause low side pressure to rise beyond safe limits during system shutdown.

Low pressure cutoff switch

The low Pressure cutoff switch shuts the compressor down when refrigerant levels drop too low. Since the A/C systems use the refrigerant to carry lubrication, running the system without an adequate charge can cause compressor damage. This switch prevents the compressor from running when refrigerant levels are too low to provide enough lubrication.

High Pressure Cutoff Switch

Some vehicles have high pressure cutoff switch designed to shut the system off if pressures get too high. Once pressures drop back to normal, the switch will allow the compressor to operate as designed. Look for this switch on the discharge muffler’s service port, or mounted on the back of the compressor.

What causes an air compressor to lock up?

 

  1. Lack of lubrication
  2. Cooling system poor performance
  3. Condenser fan not working or performing poorly
  4. A/C system overcharged
  5. Incorrect type of oil
  6. Low refrigerant charge
  7. A/C system contamination(A/C refrigerant cross contamination (Charging R-134a refrigerant into R-1234YF refrigerant.)
  8. Inefficient condenser
  9. Dirty evaporator core (In the past, not much attention was paid to dirty evaporators. Technicians are now beginning to realize that low evaporator pressures cause high compression ratios.)

 

How to find an automotive compressor problem, before is too late?

 

Compression ratios are used to compare pumping conditions for a compressor. When compression ratios become too high, the refrigerant gas temperature leaving the compressor rises to the point that oil for lubrication may become overheated. Overheated oil may turn to carbon and create acid in the system shortening the life of the Automotive A/C system.

R-134a

Ambient temperature

High Side Pressure

 

Low Side Pressure

 

90 °F/32°C      250-270 psi /1724-1862 kPa   45-55 psi / 310-379 kPa

Calculation:

Calculation example:

Compression ratio = Absolute Discharge

 

Absolute Suction

 

 

 

CR= 250 psig + 14.7 atmosphere

 

45 psig + 14.7 atmosphere

 

 

 

CR = 264.7

 

59.7

 

 

 

CR = 4.43:1

 

 

 

Understanding the A/C compressor compression ratio results.

 

A compression ratio of 4.43:1 would indicate to a service technician that the absolute or true discharge pressure is 4.43 times as great as the absolute suction pressure. Either an increase in head pressure or a decrease in suction pressure will cause higher compression ratios.

 

Symptoms of a Bad or Failing AC Compressor

 

Growling noise with compressor disengaged

Whistling noise

Grinding noise

Squealing noise

Rattling noise

Growling noise with compressor engaged

Banging noise

Knocking noise

What do automobile engine manufacturers think about the use of oil “Stop Leak” products ?

ac stop leak

What Manufacturers think about the use of a/c “Stop Leak” ?

Refrigerant must be 99% or more, pure, anything less than this value is considered a contaminated refrigerant and therefore contaminated air conditioning system.Any warranty on the car’s ac system will be automatically void if any type of sealer is found in the system.

A/C stop leak.

Vehicle and A/C part manufacturers do not endorse the use of sealants. Sealant is made to plug small holes by hardening when it contacts the moisture in the air. The problem is that a leaking system has absorbed a lot of moisture and spread into every component of the air conditioning. The sealant reacts with moisture inside a condenser or other component, creating a restriction in the normal flow of refrigerant. They will weaken rubber parts, have no effect at all, or create larger particles that will clog the filters, orifices tubes, screen protections and other parts of the AC System.

Flushing the sealant out from the ac system.

Once installed it is difficult, if not impossible to remove all the sealant from the system. There is a big risk of contaminating and damaging a new ac compressor even after the entire system has been flushed. Some air conditioning components like parallel flow condensers or evaporators are virtually impossible to effectively flush.An small and inexpensive service valve core leak could become a time consuming repair job because of the use of “a/c stop leak” products.

Contaminated refrigerant symptoms.

Some of the symptoms of a contaminated air conditioning system are: reduced cooling performance, evaporator ,thermal expansion valve or orifice tube freeze-up, intermittent cooling, increased compressor noise, higher than normal or lower than normal pressures, and premature compressor failure.

Motor Vehicle AC repairs.

Many shops will refuse to even connect their recovery machine to your car’s ac system if they suspect the use of sealant. Sealants could do really expensive damage to recovery equipment creating a huge problem for repair shops.

Why would my car not blow air until after I hit a bump?

motor vehicle repair near me

Blower motor only start working after i hit a bump.

In most cases that is a sign of worn down blower motor brushes not making a good contact. In some cases the blower motor/resistor pigtail could cause erratic operation of the blower motor too.

What is a blower motor?

The blower motor is a simple squirrel cage type of fan, DC electrical motor. It is located underneath the dash, usually inside the hvac case. Depending on the vehicle, there could be more than one blower motor

What is the function of the blower motor?

Ram air flowing through the evaporator does not provide enough air flow inside the vehicle for cooling purposes so the blower motor forces air past the evaporator and the heater core and out of the vents.

What are the main causes of a blower motor failure?

Noise from the blower motor due to a bad bearing or debris in the fan. A restriction in the cabin air filter that causes internal failure of the blower electrical parts and poor grounds are the main causes of failure and replacement of this air conditioning component.

If your car’s AC compressor needs to be replaced, what else should be replaced at the same time to avoid any other problems?

Is my ac compressor working ok

What components should be replaced to avoid any other problems with the new compressor?

 

  • Compressor
  • TXV(Thermal Expansion valve/FOT(Fixed Orifice Tube)
  • Receiver-drier / Accumulator
  • Seals at every connection open(O-rings /washers)
  • Condenser
  • Flush A/C lines
  • Balance compressor oil and A/C components replaced oil
  • Pull a deep vacuum
  • Recharge

The AC compressor should last for the entire life of the car, usually 8-10 years. Before installing a new air compressor we need to investigate what caused the failure in order to avoid future issues.

What causes an air compressor to lock up?

 

Lack of lubrication

Cooling system poor performance

Condenser fan not working or performing poorly

A/C system overcharged

Incorrect type of oil

Low refrigerant charge

A/C system contamination

A/C refrigerant cross contamination (Charging R-134a refrigerant into R-1234YF refrigerant.)

Inefficient condenser

Dirty evaporator core (In the past, not much attention was paid to dirty evaporators. Technicians are now beginning to realize that low evaporator pressures cause high compression ratios.)

 

The compressor’s efficiency can be improved by maintaining the correct working conditions. This involves keeping the suction pressure as high as practical and the head pressure as low as practical within the design parameters.

When a compressor begins to have an internal failure. It often releases debris into the A/C system. The debris created can be metal or Teflon. When enough debris is present, it can become trapped in the various components, and restrict the flow of refrigerant and oil.

After a catastrophic compressor failure the system must be flushed, otherwise the new air conditioning compressor could get damaged by all the debris released by the old locked up a/c compressor.

Most vehicle manufacturers recommend closed loop flushing with refrigerant as a flushing agent. A benefit of this type of flushing is there is no danger of flush contamination, since the flush agent being used is the correct refrigerant for the A/C system.

Fix what is causing the air conditioning compressor to fail.

Some common problems automotive a/c compressors may experience:

1-High head pressures, due to:

1.1-Overcharged ac systems.

1.2-Condenser fan not working at all or working not efficiently enough.

1.3-Clogged up with road debris, condenser core.

1.4-Contaminated a/c systems, with non-condensable gases.

2-Frequent clutch cycling due to:

2.1-Low refrigerant charge.

2.2-Faulty cycling switch.

3-Lack of lubrication or incorrect type and oil viscosity.

4-High resistance in clutch ground circuit.

5-Compressor bearing contaminated with other engine fluids (coolant, power steering…etc)

How does a car’s air conditioning system know when to kick in to cool off the inside of the car? Or does it just run continuously as long as you have the AC on?

Car A/C Repair near me

Controlling modern air conditioning systems.

For many years, the air conditioning compressor was controlled directly from the dashboard; when the A/C button was pushed, voltage would typically travel from the control head through the evaporator switch, the protection switch and through the compressor clutch to ground.

But that changed with the advent of on-board control computers, and since the 1990s, the compressor clutch on most passenger vehicles has been controlled by or through the engine computer. Today HVAC controls are being integrated into the vehicle’s total electrical system.

In modern control circuits, engaging the dash button only sends a request signal to the compressor clutch. When the request signal is received, the control module will check a number of data values to determine if the compressor clutch should be enabled. If all conditions are correct, the control module will ground the A/C control circuit relay which energizes the ac compressor clutch.

Hvac Control Head

The hvac control head (Climate control set or A/C climate control) is used for operator input. It may be an electronic module that contains a microprocessor, or simply contain switches and knobs.

The control head A/C request signal may be sent to the body control module (BCM) and then to the power train control module (PCM) to activate the A/C compressor clutch.

When the operator selects A/C on the control panel, an A/C request is sent to the PCM (Power train Control Module).If the pressure/temperature in the Air conditioning system is within specifications, and the engine operating conditions are within the programmed parameters, the PCM will allow the compressor clutch to engage.

The PCM will constantly monitor inputs from various engine sensors, including coolant temperature, throttle position, intake air temperature, and power steering system pressure, but is not limited to this only.

The PCM will also monitor A/C system pressure using various sensors and switches. These inputs will determine if system pressure is in the correct range to allow the air compressor clutch to engage, and if the cooling fans should be operating

Relays

Relays are necessary on computer controlled systems. Computers are not designed to carry large current loads; the control circuit in the relay uses low current to close the load contacts. This small current flow allows the systems to use smaller gauge wires, and micro switches that do not have to carry large amounts of current. This saves weight and helps to reduce tailpipe emissions, as well as improving fuel economy.

The clutch will be controlled by a relay or a field effect transistor (FET).In most cases, the PCM will control air compressor clutch engagement through a relay. The control side of the relay is activated by a circuit in the PCM.When the control side is closed, the contacts in the relay close, and voltage is fed to the clutch.

Relays are remoted-controlled electrical switches. They are used to connect source voltage to an electrical load when the control circuit in the relay is energized.

When the control circuit is completed, and electromagnet pulls the movable contacts of the load circuit closed. When the control circuit is open, a spring opens the contacts on the load side.

Some automotive computer inputs. Engine management operation.

  • Potentiometers
  • Variable Resistors
  • Voltage Generators
  • Switches
  • Switches
  • Serial Data
  • Frequency Generators

How long should an air conditioner compressor last in a car?

The AC compressor should last for the entire life of the car,usually 8-10 years.

System maintenance and compressor efficiency

 

The compressor’s efficiency can be improved by maintaining the correct working conditions. This involves keeping the suction pressure as high as practical and the head pressure as low as practical within the design parameters.

A dirty evaporator will cause the suction pressure to drop. When the suction pressure goes below normal, the vapor that compressor is pumping become less dense and gets thin (sometimes called rarified vapor).The compressor performance declines. Low suction pressures also cause the high-pressure gases caught in the clearance volume of the compressor to expand more during the piston’s downstroke.This gives the compressor a lower volumetric efficiency. These gases have to expand to a pressure just below the suction pressure before the suction valve will open. Because more of the downward stroke is used for reexpansion, less of the stroke can be used for suction. Suction ends when the piston reaches bottom dead center. Low evaporator pressures cause high compression ratios.

Dirty condensers also cause compression ratios to rise, but they do not rise as fast as with dirty evaporator.A dirty condenser makes the head pressure to rise. This causes the amount of refrigerant in the clearance volume (at the top of the compressor cylinder) to be greater than the design conditions allow and the compressor efficiency to drop.

If there is a dirty condenser (high head pressure) and a dirty evaporator (low suction pressure), the compressor will run longer to keep the refrigerated space at the design temperature. The overall efficiency drops.

Evaporator core and condenser core maintenance will increase the life of the air conditioning compressor,improve the A/C efficiency and cooling capacity.With regular A/C maintenance we are saving money in the long run and getting the most out of the air conditioning system.

What does this mean If a car suddenly begins to blow hot air when you turn on the A/C, then sometimes it blows cold air for a little while?

A/C blowing hot air.Why?

We need to make sure what is the sequence of events here, because the cause could be different.

After car startup A/C blows hot then sometimes blow cold.

 

What does an AC actuator do?

The AC actuator moves air distribution doors to two or more positions to direct air flow for heating and A/C vents. The AC actuator is located underneath the dashboard attached to air distribution doors in the hvac box.

Doors can control hot air/cold air blending, recirculated/fresh air control, or dual zone splitting. The motors can move the doors into many different positions, or just two.

What are the symptoms of a bad actuator?

Air coming out from the wrong vents, clicking noises coming from behind the dashboard or not being able to control the temperature(Climate control set on cold position but blowing hot air) or re-circulated or fresh air mode in your car is a sign of a bad air door actuator motor. Exhaust or outside road fumes inside the cabin.

What are the symptoms of a bad temperature blend door actuator?

Air conditioning temperature can’t be regulated. The driver, passenger or both, depending on the design won’t be able to control the temperature on their climate zone. Decreased air conditioning performance due to improperly mixed of hot and cold air inside the hvac box.

How to test the blend door actuator motor?

There are some simple tests that could be done in order to determine if the vehicle is having issues with the blend door actuator:

If you can’t set the temperature from the head control set selector, there is a problem with the blend door actuator, the blend door, the head control set or the circuit connecting them.

For every movement of the knob on the climate control set corresponds a movement on the blend door. If there is no movement, there is a problem with the blend door actuator, the blend door, the climate control set or the circuit connecting them.

As the blend door open or closes to the heat or cold position it opposes the flow of air coming from the blower motor and makes a change in the intensity of the air noise. If you can’t hear this change in air noise intensity there is a problem with the blend door actuator, the blend door, the climate control set or the circuit connecting them.

After car startup A/C blows cold then sometimes blow hot.

 

The low-pressure / temperature sensor will interrupt compressor operation if system pressure drops to the point that a loss of refrigerant charge to the compressor occurs.The high-pressure cut-out  sensor interrupts compressor operation in case of extremely high system pressure.

Cycling clutch pressure  switch controls compressor pressures operation.It keeps the refrigerant pressure  between 47 psi-26 psi.This cycling action maintains the evaporator at 33 °F.

Some air conditioning systems use a thermostatic clutch cycling switch that cycles the compressor on and off in relation to evaporator outlet temperature.

What causes an air compressor to lock up?

 

Auto air conditioning compressor

cropped-20181024_1642160.jpg

What causes an air compressor to lock up?

 

  • Lack of lubrication
  • Cooling system poor performance
  • Condenser fan not working or performing poorly
  • A/C  system overcharged
  • Incorrect type of oil
  • Low refrigerant charge
  • A/C system contamination
  • A/C refrigerant cross contamination (Charging R-134a refrigerant into R-1234YF refrigerant.)
  • Inefficient condenser
  • Dirty evaporator core (In the past, not much attention was paid to dirty evaporators. Technicians are now beginning to realize that low evaporator pressures cause high compression ratios.)

 

 

Analysis of Denso A/C Compressor warranty claims shows that in a quarter of all cases
the use of incorrect oils, such as universal oils or oil mixtures, inevitably leads to seizure and damage. This is because universal oils are PAO-oils or mineral oils with a different viscosity to that of synthetic PAG-oils. PAO-oils do not mix well with PAG-oils and with refrigerant R134a or R1234yf, leading to poor lubrication and increased wear. Installing the ac Compressor without balancing the oil in the system, gives a high risk of liquid lock, due to too much oil in the A/C system! When adding oil to the ac compressor in your car one out of two methods could be used and the right one will depend on the type of compressor. Oil could be added through the ac compressor oil service port or through the low side or intake of the compressor. Always add oil through the oil service port if it comes with one or compressor damage may result.

 

Excessively high temperature and lack of lubrication are the biggest enemies of any automotive a/c compressor bearings. Slipping compressor clutches can generate temperatures as high as 1,200 degrees Fahrenheit; this tremendous amount of heat will quickly melt down the bearing seal. The bearing loses its grease and in the process, before it locks up completely it gets rough and noisy.  Seal could cause the compressor oil to finds it way into the hvac compressor clutch bearing contaminating the grease. The properties of the bearing grease will be changed by this oil contamination causing it a poor compressor bearing lubrication and inevitably internal bearing failure.

 

Leaking air conditioning systems will leak out refrigerant and the oil that resides inside of the compressor creating a huge frictional resistance between the compressor piston and the cylinder leading to an increase in compressor internal temperature

 

Overcharged or improperly vacuumed auto ac systems will create high system pressures and therefore high temperatures.

 

Compressor pressure plate and rotor pulley excessive air gap will cause slippage and rise in temperature.

 

A dirty evaporator will cause the suction pressure to drop. When the suction pressure goes below normal, the vapor that the compressor is pumping becomes les dense and gets thin (sometimes called rarified vapor).The compressor performance declines. Low suction pressures also cause the high-pressure gases caught in the clearance volume of the compressor to expand more during the piston’s downstroke.This gives the compressor a lower volumetric efficiency. These gases have to expand to a pressure just below the suction pressure before the suction valve will open. Because more of the downward stroke is used for expansion, less of the stroke can be used for suction. Suction ends when the piston reaches bottom dead center.

 

 

 

How to save my auto air conditioning compressor?

 

A/C performance test

 

 

This easy test will give you a general guideline to compare against your car’s a/c operation. (This test was specifically performed on a BMW model).

 

 

Switch on air conditioning compressor with A/C button at a vehicle interior of 45 °C /113 °F (measure at the head restraint)

 

On vehicles with MAX-AC button:

  • Activation of  MAX- AC (= maximum cooling power)

On vehicles without MAX-AC button:

  • Set Maximum cooling power by means of following steps:
    • Setting low temperature value
    • Blower setting maximum
    • Stratification maximum cold(4 blue bars)
    • Only ventilation open
    • Close remaining flaps (air outlet only from center fresh air grille, left and right)

 

After 5 min, measure both ventilation temperatures with a thermometer at the same time (center, left and right fresh air grille). The measured temperature must be < 16 °C / 60.8 °F and the difference between right and left may not be greater than 2 °C / °F.

 

How to find an automotive compressor problem, before is too late?

 

Compression ratios are used to compare pumping conditions for a compressor. When compression ratios become too high, the refrigerant gas temperature leaving the compressor rises to the point that oil for lubrication may become overheated. Overheated oil may turn to carbon and create acid in the system shortening the life of the Automotive A/C system.

 

 

R-134a

Ambient temperature

High Side Pressure

Low Side Pressure

90 °F/32°C 250-270 psi /1724-1862 kPa 45-55 psi / 310-379 kPa

 

Calculation:

 

Calculation example:

 

Compression ratio = Absolute Discharge

                             Absolute Suction

 

CR= 250 psig + 14.7 atmosphere

        45 psig + 14.7 atmospheres

 

CR = 264.7

59.7

 

CR = 4.43:1

 

Understanding the A/C compressor compression ratio results.

 

A compression ratio of 4.43:1 would indicate to a service technician that the absolute or true discharge pressure is 4.43 times as great as the absolute suction pressure. Either an increase in head pressure or a decrease in suction pressure will cause higher compression ratios.

 

 

Symptoms of a Bad or Failing AC Compressor

 

  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

 

 

Serpentine belt problems usually result from one of these causes: a defective belt tensioner, misalignment of a pulley or defective bearings of any component of the drive system. Worn out drive system belts lead to poor hvac compressor output performance.

 

Can compressor be repaired?

 

The air compressor may be remanufactured or rebuilt. The price range for labor only is $285.00 to $500.00.This is an option many people choose, because of the price difference between a new compressor and a rebuilt one.

 

 

What happens if a compressor fails?

 

The first sign will be no cold air coming out from the vents.

These are all signs that a/c compressor in your car is about stop working or fail:

 

1-Clicking sound from under the engine. (Compressor clutch engaging and disengaging)

2-AC not working.

3-Noise under the engine with the a/c climate control on.

4-Burned rubber smell coming out from the engine compartment.

5-Looking at ac gauges set pressure; typical weak or damaged ac compressor pressures are High side pressure too low and Low side pressure too high.

 

When a compressor begins to have an internal failure. It often releases debris into the A/C system. The debris created can be metal or Teflon. Metal debris can be created from any metal component inside the compressor sefl-desctructing, and Teflon can come from the Teflon seals on the compressor pistons. When debris becomes trapped against the seal, it will damage it and pieces of the seal break apart and travel throughout the A/C system.

When enough debris is present, it can become trapped in the various components, and restrict the flow of refrigerant and oil.

 

After a catastrophic compressor failure the system must be flushed, otherwise the new air conditioning compressor could get damaged by all the debris released by the old locked up a/c compressor.

Most vehicle manufacturers recommend closed loop flushing with refrigerant as a flushing agent. A benefit of this type of flushing is there is no danger of flush contamination, since the flush agent being used is the correct refrigerant for the A/C system.

 

When the A/C system flushing is complete:

 

  • Oil balance the system through the compressor.
  • Reconnect the manifold line to the compressor, or replace the compressor if needed.
  • Install a new orifice tube or TXV.
  • Install a new Accumulator-drier or Receiver-drier

 

 

 

Why did my compressor stop working?

  • Electric or electronic fault of any of the compressor control devices or ac compressor circuit protection device
  • Faulty or wrong signal input to the BCM or PCM.
  • A/C compressor clutch excessive air gap.
  • A/C system too low on refrigerant charge due leakage in the air conditioning system.
  • Compressor clutch coil winding open.
  • A/C head control set switch damage or entire a/c control set damaged.
  • Variable displacement electronically controlled compressor. Valve control damaged.

 

 

 

 

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.