What causes an ac compressor to lock up
Inaccurate refrigerant(freon) charges increase the chances of auto ac compressor lock up. Modern auto a/c systems require super accurate charging. Being off as little as 2 ounces can cause problems.R-134a and R-1234yf ac system tolerances require charge rates that must remain or should be charged within +/- 5% of OEM recommendation. SAE J2788 requires charge accuracy of +/- one-half ounce.
Attempting to charge by cans is History !!
Car ac compressor lock up due to improper compressor lubrication.
Refrigerant moves the oil inside the ac system and helps to cool down the ac compressor. An undercharge or overcharge refrigerant condition will increase the air conditioning compressor temperature and a change in oil viscosity and lubrication characteristics. Most compressor lock ups are the result of a lubrication problem.
AC compressors lock up due to ac system contamination
Auto ac compressor damage may occur because of system contamination. Anything more than the correct type of freon and oil is a contaminant. The use of sealers to fix small refrigerant leaks will cause oil and refrigerant contamination and ultimately ac compressor lock up. Sealer can’t be removed from the A/C systems. The contaminated components must be replaced.
The use of excessive Dye to help finding leaks in the ac system could create a contamination problem as well, increasing the normal working pressure of the ac compressor and the overall efficiency of the air conditioning system.
Improperly replacing any component in the automotive air conditioning system where the system must be opened for replacement of the damaged part and not evacuating the system before recharging it with the proper amount and type of refrigerant will contaminate the ac system with air. Air and moisture inside the system will create excessively high operating pressures and temperatures and eventually could lead to a compressor lock up.
Inefficient ac condensers and air conditioning compressor lock up
Debris on the condenser will affect the desuperheat, condensation and subcooling processes happening in the auto ac condenser.AC condenser with bent or missing fins will be unable to efficiently operate. An inefficient ac condenser will cause an auto ac compressor to lock up.
Low Refrigerant charge and electronically controlled compressor lock up ?
The car engines in vehicles with the clutchless compressors should not be run without refrigerant in the A/C system. Without refrigerant to move the oil, the auto ac compressor may not be properly lubricated and compressor lock up may result.
Do you need assistance inspecting the state of your ac compressor in your vehicle?
Call Us today ! We have automotive ac specialists near you.
Low refrigerant charge causes rapid cycling. Drive belts and blower resistors do not affect compressor cycling. An excessive air gap may prevent the clutch from engaging.
Do you need assistance with your car ac ?
Call Us today ! We have auto ac mechanics near you.
- A/C Compressor stopped working on my 2008 Toyota Camry L4-2.4L.
- Why is there no heater in my car?
- Why is my Hyundai Santa Fe AC not blowing air from the vents?
- How can I check my car’s air conditioning system’s freon level without opening the hood?
- How to extend the life of your vehicle ac compressor
Auto A/C Repair LLC. Blog
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A Common Reason for a failing car a/c compressor.
The most common reason for Electronic controlled A/C compressors is the failure of the Electronic Control Valve (ECV).
Issue: The A/C Compressor stopped working.
Cause: A/C Compressor (ECV) Electronic Control Valve faulty.
ELECTRONIC CONTROLLED VARIABLE DISPLACEMENT CLUTCHLESS COMPRESSOR AND LACK OF LUBRICATION
Electronic controlled variable displacement compressors could be clutch or clutch-less designs. The ac compressor has a swash plate that rotates to reciprocate pistons, which compress refrigerant. The swash plate is allowed to change its angle which changes the stroke rate of the piston. They are electronically controlled using sensors and an Electronic Control Module (ECM)
Electronic controlled variable displacement compressor is always running even when the a/c is off. The ECM changes the rate of displacement, but the compressor is spinning connected to the drive belt without any clutch to disengage.
Lubrication occurs by using a sump in which the connecting rod splashes oil around the inside of the compressor. Some automotive air conditioning compressors use an oil pump to circulate the oil, like an engine lubrication system. Lubrication is accomplished while the ac compressor is running and there is refrigerant and oil circulating back to the compressor.
The (ECVD) clutch-less compressor should not be operated without refrigerant in the system to carry lubricant.
How to Fix it ?
When the A/C Compressor (ECV) Electronic Control Valve is faulty is recommended to replace the entire a/c compressor to prevent future (ECV) valve failures.
Do you need assistance?
Why is there no heater in my car?
Issue
Insufficient heat from a/c system in my 2012 Volvo C30 T5 L5-2.5L Turbo.
Cause
Heater coil was restricted.
Fix
Heater Coil replacement.
Common reasons.
- Faulty Engine Thermostat
- Faulty heater control valve
- Faulty Heater door
- Faulty Heater door actuator
- Clogged Heater core
How to diagnose and narrow down the possibilities?
Clogged Heater
- Start the vehicle
- Let the engine run for 15-20 minutes.
- Locate Heater coil inlet and outlet lines.
- Measure the temperature difference between the inlet and outlet lines.
- If there is a noticeable temperature difference between the inlet and outlet lines, the heater coil is restricted internally preventing the hot coolant from the engine from circulating through the coil.
Faulty Heater control Valve
- Start the vehicle
- Let the engine run for 15-20 minutes.
- Locate the heater control valve.
- Measure the temperature difference between the inlet and outlet lines.
- Check that heater control valve is actuated by the control in the OPEN position.
- In the OPEN position there should be about the same temperature between the inlet and outlet lines.
- If there is a noticeable temperature difference between the inlet and outlet lines, the heater control valve is not opening or closing or the valve is restricted internally preventing the flow of hot coolant.
Faulty Engine Thermostat
A stuck open engine thermostat will prevent the engine temperature to get up to specifications which will cause Heater system underperformance.
Do you need assistance?
Why is my Hyundai Santa Fe AC not blowing air from the vents?
Issue
One common reason
The A/C could not be blowing air out of the vents on a 2013 Hyundai Truck Santa Fe FWD L4-2.0L Turbo could be because of a faulty blower motor speed control module (PWM, blower resistor or control module).
What damaged the Blower motor speed control module ?
In most cases an excessive current draw from a defective or restricted blower motor could damage the blower motor resistor.
How to fix it ?
In many cases the blower motor speed control module is replaced together with the blower motor to prevent the blower motor from damaging the blower motor control module in the near future.
Do you need assistance with your ac system in your vehicle ?
With modern automotive a/c systems you no longer need to open the hood to know what is happening with your car’s AC system. Any automotive scanner could be connected to the OBDII Port and give you access to almost all the information you need to determine the state of charge of your car’s AC system from the different modules.
The activation and operation of the A/C Compressor of the vehicle’s A/C System is ultimately determined by the PCM. The PCM reads inputs from different modules and sensors and enables or prevents A/C compressor activation.
The PCM controls the ground side of the A/C clutch relay coil circuit. When this circuit is completed to ground, the relay switch contacts close, and power is supplied to the compressor clutch.
How can I tell if my car’s air conditioning AC system is running low on refrigerant?
A/C Pressure Sensor Voltage Output.
| VOLTAGE | CONDITION |
| 0.00 | · Faulty Sensor. · No 5V Reference from PCM. · 5V Reference Open or Shorted. · Feedback Signal Open or Shorted. |
| 0.150-0.294 | Low-Pressure Cut-Out Voltage (Sensor OK) |
| 0.295-4.310 | Normal Operating Range. |
| 4.311-4.850 | High-Pressure Cut-Out Voltage (Sensor OK) |
| 5.00 | · Faulty Sensor. · Open Sensor Ground. · Feedback Signal Shorted to Voltage. |
With The Scanner connected to the OBDII port
- Get Access to the A/C Pressure Sensor values with the A/C ON and engine running
- Compare the values from the Scanner with the values from the table.
- Readings below 0.150 may indicate a low refrigerant condition and the PCM may prevent the A/C Compressor from operating to avoid compressor damage.
- Readings below 0.150 may indicate a weak A/C compressor unable to rise the A/C pressure in the system.
- Readings below 0.150 may indicate that the compressor is off.
- 295-4.310 readings and fluctuations in the voltage values indicate that the compressor is operating and the A/C system freon charge is within normal ranges.
- Readings above 4.310 indicate a freon overcharge condition or a condition where the A/C system pressure is above the normal operating range.
The location of the A/C Pressure Sensor.
The A/C Pressure Sensor is threaded onto a valve located in the discharge line near the A/C condenser. It is a 0-500 psig. transducer that converts A/C high-side pressure into an electrical signal. If the high side pressure is either too high or too low, the PCM will not enable the compressor clutch.
How can I determine if the A/C pressure sensor in my car is functioning correctly?
The A/C Pressure sensor is supplied with a 5V reference signal from the PCM. It will vary the 5V signal based on changes it senses in high-side pressure. The voltage will rise as pressure increases. If the pressure rises above approximately 430 psig or drops below approximately 30 psig, the PCM will disable the compressor clutch. The sensor signal to the PCM will be approximately 1.2 volts with A/C off and between 1.5 and 2 volts with A/C on.
Would you like help with your vehicle’s air conditioning system?
We specialize in automotive A/C systems. We Operate in South Florida. Call Today!
Does a car AC compressor have a pressure relief valve?
Yes, automotive ac compressors have a pressure relief valve installed on their body.
What does an ac compressor relief valve in a car do?
The AC pressure relief valve is a safety device that protects the compressor from operating above its designed Maximum operating/working pressure.
The high -pressure relief valve is used to keep the system pressures from reaching a point that may cause compressor lock-up or other component damage because of excessive high pressures. When ac system pressures in a vehicle exceed a predetermined point, the pressure relief valve opens, venting refrigerant and reducing the ac system pressure .
The ac pressure relief valve in a car can fail in 3 different positions.
- Pressure relief valve stuck fully open.
- Pressure relief valve partially open.
- Pressure relief valve stuck closed.
What happens if the pressure relief valve fails ?
Signs of the ac compressor pressure relief valve failure
- Pressure relief valve stuck fully open.
In this condition, the ac compressor will not be able to pressurize the ac system. The ac system will not hold the refrigerant charge for a long enough period to allow the ac compressor to raise the refrigerant pressure to normal ac operating pressures.
- Pressure relief valve partially open.
In this situation ,the ac compressor relief valve remains partially seated. This condition is the most difficult to diagnose. The a/c compressor will operate and pressurize the system up to normal operating pressures and the overall performance of the car a/c system will be excellent but will slowly decrease over time ,because of the refrigerant leaking out from the not fully closed relief valve.
- Pressure relief valve stuck closed.
This could result in a dangerous condition. The ac compressor pressure relief valve is a safety device intended to keep the refrigerant pressure circulating inside the ac system by the compressor below a dangerous point. The relief valve is the last safety resource used by the car manufacturer to vent the refrigerant out into the atmosphere before an ac component exceeds its safe working pressure and explodes. The ac compressor pressure relief valve is usually activated after all the other safety devices in the car were unable to stop the ac compressor operation.
Why is my air compressor pressure relief valve leaking ?
The air compressor pressure relief valve is a spring self-resetting device. The intended operation of the valve is to open when the refrigerant pressure inside the ac system exceeds a maximum pressure point ,usually between 350 PSI to 600 PSI. The normal operation of the relief valve is to open and vent refrigerant out into the atmosphere when the pressure exceeds the maximum level. The relief valve should reset automatically to the fully closed position when the refrigerant pressure is less than the internally calibrated spring force. In many cases once the valve opens it will not return perfectly to the fully closed position creating a refrigerant leaking point in the virtually sealed ac system.
What does the ac compressor pressure relief valve tell me about the overall condition of the ac system ?
- Engine cooling system affecting a/c performance
- Inoperative radiator fans
- Underperforming fan clutches
- Freon overcharge
- A/C system contamination
- A/C system contaminated with non-condensable gases
An ac compressor pressure relief valve fault should be the beginning of a deeper vehicle ac system diagnostic. A leaking pressure relief valve is a warning about an excessive high pressure in the ac system. Overlooking the warning sign of the valve could lead to expensive repairs in the automotive a/c system.
What happens when the ac compressor pressure relief valve in a vehicle is venting freon ?
- A/C internal compressor failure
- High side components leaking
- A/C poor performance
- A/C system contaminated with debris from internal compressor components.
Internal a/c compressor failure and system contamination often follows a leaking valve or indications of refrigerant venting from the valve. The cause of the valve opening condition should be found and repaired.
How to set the pressure relief valve on a car air compressor ?
The ac compressor pressure relief valve is calibrated by the manufacturer and there is no need to calibrate or repair. If the valve is leaking or faulty ,it should be replaced.
Do you need assistance with the ac system in your vehicle ? We offer automotive air conditioning service in South Florida. Call today!
What are normal car ac repair prices in Miami?
The average costs for common car A/C repair services in Miami are:
A/C Repair – $384 to $445
A/C Compressor Replacement – $1,546 to $1,705
A/C Recharge – $239 to $281
*This data is based on Kelley Blue Book’s Fair Repair Range.
How can I spend less on my car ac system repair?
- Our mechanics offer mobile car ac repairs in Miami.
- We have significantly lower overhead costs compared to the conventional local shops.
- Your gender doesn’t determine the cost of auto ac repair.
- Our price doesn’t change even if it takes longer to complete the job than estimated.
- We offer 1 year warranty on parts and labor.
- Prior to any repair we will provide you with the detailed cost of labor, parts, and taxes. You’ll know exactly what’s included in your service so there are no surprises.
Why is fixing an ac in a car so expensive ?
The cost of car ac repair will vary depending on :
- Make and model of the vehicle.
- Type of vehicle. Internal combustion engine (ICE) prices are cheaper compared to Electric vehicles (EV) or hybrid vehicles.
- Labor/Time to replace or repair the ac component.
- The type of refrigerant used in the vehicle’s ac system.R134a is cheaper compared to R1234yf.
- The price of the ac component that needs to be replaced. Original Equipment Manufacturer (OEM) are more expensive than Aftermarket components.
Car ac repair in Miami ?
We service almost all areas in Miami-Dade County. Call us today to set an appointment!
- Doral
- Miami Lakes
- Hialeah
- Coral Gables
- Hialeah garden
- Downtown
Most common automotive ac type of problem ?
These are the most common car ac components failures and repairs :
- Refrigerant leaks
- A/C Compressor failure.
- A/C system contamination.
What are Symptoms of a bad car air conditioner ?
Symptoms of a bad car air conditioner due to :
Leaks
- The ac system performance is greatly decreased.
- The driver and passengers start to smell some particular odor that is often described as the odor coming from a room that is been locked for a long time.
- In cars with dual ac units another sign is that the front unit stops blowing cold air first while the back unit still blows some cool air.
- in cars with front ac unit only, the vents from one side of the car blows colder than the other one.
- Compressor cycling on and off too often.
- Frost in a/c lines.
- Visible refrigerant (Freon) leaks
Compressor
- The ac system performance has greatly decreased.
- Noise coming from the engine compartment with the ac on.
- Burnt rubber or plastic smell coming from the engine compartment with the a/c on.
A/C system contamination.
- The ac system performance has greatly decreased.
- A/C system stop working or a decrease in performance is noticed after the ac system was serviced.
Do you need assistance with the A/C in your vehicle ?
A/C RECHARGE SERVICES AT AUTO AC REPAIR LLC.
If you need to recharge the a/c system in your car, Call Us Today. Auto A/C Repair LLC. Technicians come to your home or office in Miami and will service the AC in your vehicle at your place.
Auto A/C Repair LLC. technicians will :
- Recover the old refrigerant from the vehicle AC system.
- Vacuum the car AC system to make sure there is no moisture or non-condensable gases in the AC system.
- Recharge the car AC system with the exact refrigerant amount recommended by the manufacturer
- After the Air conditioning system is recharged up to manufacturer specifications, the technician will check the AC system operating pressures.
- The technician will do an AC system oil balance.
WHAT IS AN A/C RECHARGE?
The A/C Recharge service will bring the amount of refrigerant and oil circulating in your vehicle’s AC system up to the exact manufacturer specifications. The refrigerant is where the heat from the vehicle’s cabin is stored and moved out to the outside of the vehicle where is transferred to the outside ambient air. To cool down the driver and passenger compartment fast and properly the exact amount of refrigerant specified by the manufacturer must be circulated in the air conditioning system.
HOW DO YOU KNOW IF YOUR CAR’S A/C NEEDS TO BE RECHARGED?
- The AC system is not cooling down the interior of the vehicle as fast as it used to.
- The car interior temperature never gets cold enough.
- A low freon charge could be the result of a leak in any component of the car ac system.
- A/C compressor turning on and off fast(Compressor Over cycling).
Properly fixing a low freon condition involves more than just recharging the a/c system. If there is a leak in the system it must be fixed, otherwise the freon charge could only last a couple hours or days before it is low again.
Refrigerant leaks and refrigerant oil leaks happen together ,just at different rates. Recharging the freon in the car ac system without balancing and recharging the oil could lead to compressor failure
HOW OFTEN DOES A CAR A/C NEED TO BE RECHARGED?
You will need an AC freon recharge as soon as the system is low or after any repair that involves opening the closed loop sealed air conditioning system is performed in your vehicle.
WHY YOU SHOULD LEAVE IT TO THE PROFESSIONALS
The only accurate method to recharge an automotive a/c system that requires a critical charge is to weigh the refrigerant (Freon) into the system using a manifold gauge set and calibrated special scale for this purpose. Recharging the a/c system by pressure, which is the method used when the system is recharged using small refrigerant can and a gauge is inaccurate, and virtually impossible to charge the system according to manufacturer specifications.
WHERE TO GET AN A/C RECHARGE
Is it time to get your vehicle’s air conditioning system recharged ? Schedule an appointment today at Auto A/C Repair LLC. for car A/C Recharge and repair services. One of our ASE certified technicians will come to your home or office to perform the service at your place.
This is a list of the most common car a/c failures that lead to a no cooling ac condition in any vehicle:
- A/C Refrigerant leaks
- A/C Refrigerant contamination
- A/C Refrigerant overcharge condition
- A/C system non-condensable gases contamination
- A/C refrigerant oil ,overcharge condition
- Weak A/C Compressor
- Faulty valve, on electronically controlled variable displacement a/c compressor
- Faulty A/C Compressor Clutch Relay
- Faulty A/C Compressor clutch coil
- Inoperative A/C Compressor
- Engine cooling system affecting A/C operation
- Leaking Heater valve
- Externally restricted A/C Condenser
- Internally restricted A/C Condenser
- Externally restricted engine cooling radiator
- Faulty Outside Ambient Temperature sensor
- Faulty Pressure sensor/switch
- Faulty Evaporator Temperature Sensor
- Faulty electric wiring
- Open fuses
- Restricted A/C Cabin-filter
- Restricted evaporator coil
- A/C Door Actuator malfunction
- A/C Temperature Door Actuator stuck in the heat position
- Faulty Expansion Valve
- Faulty Fixed Orifice Tube
- Bad drive belt tensioner
- Worn down a/c compressor drive belt
Why is my car AC running but not cooling?
Newer automotive air conditioner systems have the a/c compressor always operating. The a/c compressor pulley is constantly rotating but the a/c compressor output is controlled in many cases by the ECM or the PCM in the vehicle. The Powertrain control module (PCM) or Electronic controlled Module (ECM) will receive input from different sensors in the vehicle and will command a/c compressor output accordingly.
Do you need assistance with a poor a/c cooling performance ?
Call Today to set an appointment for a complete air conditioner system checkup in your vehicle. Early preventive service could save you a lot of money.
The only accurate method to recharge an automotive a/c system that requires a critical charge is to weigh the refrigerant (Freon) into the system using a manifold gauge set and calibrated special scale for this purpose. Recharging the a/c system by pressure, which is the method used when the system is recharged using small refrigerant can and a gauge is inaccurate, and virtually impossible to charge the system according to manufacturer specifications. Depending on the a/c system design, the pressures will be impacted by the type of compressor, metering device(Expansion Valve or Orifice tube) ,ambient temperature and humidity. Pressure controlled systems could reach pressure cycling points faster ,increasing the compressor clutch cycling and forcing the compressor to operate under higher-than-normal crankcase temperatures if the system is undercharged. Short cycling compressors will decrease the life of the compressor clutch assembly, due to more often engagement and disengagement of the clutch assembly and the compressor pulley. When the system is overcharged the evaporator will not be able to evaporate the refrigerant metered by the metering device and liquid refrigerant could reach the a/c compressor. An overcharge system will force the a/c component working pressures to the limits and could develop leaks and cause compressor damage.
Car A/C system Recharge near me
Improperly recharged car a/c systems will increase or decrease compression ratios, negatively impacting the overall health of the a/c system. Just because the air conditioner is blowing cold air, it doesn’t mean is working according to manufacturer specifications. Modern car a/c systems design have the capability to adjust their operation even when the freon recharge is not 100% accurate. The a/c system will change compressor displacement, thermal expansion valve operation ,condenser fan speed and will force the system to get to the desired temperature set by the driver. Car a/c systems working under inaccurate freon charge will have compression ratios that will stress the compressor and shorten their life. The manufacturer calculated values of superheat and subcooling happening in the evaporator coil and condenser coil will change, making it harder for the metering device to respond to the flow of refrigerant and for the compressor to receive refrigerant oil back from the evaporator needed for internal piston lubrication. Flash gas rates will be higher at the expansion valve making the valve less efficient.
Ac freon recharge near me
You will need an AC freon recharge if the system is low or after any repair that involves opening the closed loop sealed air conditioning system is performed in your vehicle. A low freon charge could be the result of a leak in any component of the car ac system. Properly fixing a low freon condition involves more than just recharging the a/c system. If there is a leak in the system it must be fixed, otherwise the freon charge could only last couple hours or days before it is low again. Refrigerant leak and refrigerant oil leak happen together ,just at different rates. Recharging the freon in the car ac system without balancing and recharging the oil will lead to compressor failure.
Do you need a Freon recharge in your vehicle ?
Our ASE certified air conditioning system specialist will take care of your vehicle’s air conditioning system. Have your system properly serviced by an air conditioning system specialist today! You can save money by servicing the a/c system following the manufacturer specifications. Call Today !