Tag: Auto ac compressor repair near me

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.

  1. Pressure relief valve stuck fully open.
  2. Pressure relief valve partially open.
  3. 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?

  1. Our mechanics offer mobile car ac repairs in Miami.
  2. We have significantly lower overhead costs compared to the conventional local shops.
  3. Your gender doesn’t determine the cost of auto ac repair.
  4. Our price doesn’t change even if it takes longer to complete the job than estimated.
  5. We offer 1 year warranty on parts and labor.
  6. 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 :

  1. Make and model of the vehicle.
  2. Type of vehicle. Internal combustion engine (ICE) prices are cheaper compared to Electric vehicles (EV) or hybrid vehicles.
  3. Labor/Time to replace or repair the ac component.
  4. The type of refrigerant used in the vehicle’s ac system.R134a is cheaper compared to R1234yf.
  5. 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.

Learn more…

What are Symptoms of a bad car air conditioner ?

Symptoms of a bad car air conditioner due to :


  • 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


  • 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 ?

Yellow Jacket manifold gauges

Auto A/C Compressors have evolved over time and the old, fixed displacement compressor has been replaced by more efficient variable displacement compressors. Pressure controlled variable displacement compressor and Electronically Controlled Variable Displacement Compressor (ECV) react in different ways compared to fixed displacement compressors when air conditioning restrictions and other common automotive a/c faults happen. Failure to identify the type of a/c compressor in the vehicle at the beginning of the diagnostic procedure could lead to unnecessary, expensive and in most cases time consuming repairs. A restricted Thermal Expansion Valve creates Manifold gauge readings that could lead to chasing a/c system leaks, unnecessary auto a/c compressor and sensor replacement.

How do I know if my compressor or expansion valve is bad?

Manifold Gauge readings

Low side LOW        High side LOW

A restricted Thermal Expansion valve gauge readings will be different in the newer Pressure controlled variable displacement air conditioning compressor.

 When a restriction in the refrigerant flow caused by a Thermal Expansion Valve (TXV) fault happens, the Pressure controlled variable displacement compressor will try to compensate the change in refrigerant pressure from the TXV by adjusting the compressor internal control valve, and keep the compressor crankcase pressure at a value where the swash plate angle based on the low side pressure is prevented from going into the condition where you see a manifold gauge vacuum reading. The manifold gauge reading in this type of system will show Low side gauge reading low and High side gauge reading low. It could be erroneously diagnosed as a weak compressor problem.

Low Side into Vacuum         High Side LOW

A restricted Thermal Expansion Valve (TXV) gauge reading on an Electronically Controlled Variable Displacement Compressor will be different due to the logic the Powertrain Control Module uses to operate and control the a/c compressor. The PCM will receive inputs from the evaporator temperature and will command signals to the ac compressor electronic control valve to adjust pumping capacity accordingly. When the TXV fails or is restricted the evaporator temperature will increase and that increase value will be sent to the PCM which in turns will increase compressor pumping capacity to 100%.The Electronically Controlled Variable Displacement Compressor will operate similar to an old ,Fixed Displacement A/C Compressor and the Manifold Gauges will show Low Side going near 0 Psig or into a vacuum reading.

How do I know if my compressor or expansion valve is bad?

  • The type of system must be identified
  • The type of a/c compressor must be identified
  • Manifold Gauge Readings must be checked
  • PWM signals to the ECV must be inspected

Avoid unnecessary expensive repairs.

The air entering the cab is only slightly cool, and there are bubbles visible in the sight glass. there is usually about an 95% chance the restriction is expansion valve failed in the closed position related, 4% chance it is drier related and 1% chance it is somewhere else along the system or  an internal drier desiccant bag rupture leading to a/c system contamination and restricting the metering orifice of the expansion valve.

Call Us today if your A/C is experiencing this symptoms! The correct diagnostic procedure will save you TIME and Money. Auto A/C Repair LLC. offers mobile a/c inspection in Hialeah,florida.

Auto A/C noisy compressor troubleshooting chart
Compressor NoisyAC compressor internal noiseBearing worn or damagedDefective cylinder/or shaftDisassembly and replace defective parts.
Magnetic Clutch Noisy.Rattling noise when magnetic clutch is not engaged .Bearing worn or damaged.Replace bearing.
Noise from pipingPiping not secured.Piping vibrating .Pulsating noise resonates into body.Secure piping.
Noise from condenserCondenser vibration prominent.Condenser mounting stay resonating with body .Secure by inserting rubber between stay and body.
Noise produced by bracket.Rattles when touched, continuous rattling heard when operating.Bracket cracked or broken.Mounting bolts loose.ReplaceRetighten bolts.
Idler pulley noisy.Clattering noise produced. Rattles when touched.Bearing broken.Bracket Cracked or loose.ReplaceReplace or retighten.
Noisy crankshaft pulley.Rattles.Improperly installed.Replace or retighten.
Belt NoisyBelt deflection excessiveBelt side surface wornBelt wornBelt wornBelt center misalignedWorn belt causing belt slipping on pulleys and tensionerAdjust tensionAlign centerReplace belt
Noisy belt tensionerSquealing belt and/or rumbling noiseTensioner bearing or tensioner spring weakReplace belt and tensioner
*Chart provided by Denso.

Do you need assistance inspecting a noisy a/c compressor ?

Call today and schedule an appointment to have your auto a/c system inspected.

What causes an ac compressor to lock up

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.

ac compressor oil

Why does the compressor cycle on and off?

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.


Auto AC Compressor Failure Symptoms

Signs of auto a/c compressor failure:

  • Cooling performance decreases
  • A/C not as cold as it used to be
  • Knocking noises from the compressor
  • Squealing A/C compressor drive belt
  • Excessively hot compressor crankcase
  • Compressor pressure plate not engaging
  • Both lines from a/c compressor at the same ambient temperature
  • Gauge pressure ,High side Low and Low side High
  • A/C compressor locked up. Compressor Does not turn when rotated by hand.
  • Compressor pressure plate signs of overheating condition
  • Compressor body signs of overheating condition

What causes A/C Compressor Clutch Failure?

Causes of A/C Compressor Clutch Failure:

  • A/C compressor over cycling.
  • Excessive high compressor temperature due to air conditioning system contamination.
  • Cooling system underperformance affecting a/c operation.
  • Drive belt slipping on a/c compressor pulley creating excessive high heat load.
  • Slipping clutch pressure plate due to out of specs compressor clutch gap.
  • Shorts to power or ground on the ac compressor clutch coil circuit.
  • A/C compressor clutch relay inoperative or shorted.
  • Inaccurate refrigerant(freon) charges increase compressor failure.
  • Lack of compressor internal lubrication
  • Incorrect type of oil
  • Incorrect or contaminated refrigerant in the air conditioning system.
  • Inefficient or restricted auto a/c condensers
  • High compression ratios

What to do if my auto A/C Compressor fails ?

Technically the compressor can be rebuilt ,it is recommended to replace the entire compressor. If there was a major internal compressor failure the entire system must be inspected for debris(metal from internal compressor components).After an internal compressor failure, it is  recommended to replace the A/C condenser(Specially if it is a modern Parallel Flow type) and the drier, to avoid contamination of the brand new air conditioning compressor. Also, the system should be flushed to avoid contamination.

Where can I Get my auto ac Compressor Replaced?

If you need assistance replacing the a/c compressor in your vehicle Call Us Today ! Auto A/C Repair LLC. operates a mobile air conditioning repair shop in Miami. Contact Us if you need to check any auto a/c compressor failure symptoms. One of our ASE certified mechanics will take care of your vehicle. We offer 1 Year Warranty on Parts and Labor.

Do new car A/C compressors come with oil?


Does the new car ac compressor contain oil?

Many auto ac compressor manufacturers list the oil amount on the label usually on the hvac compressor itself, but not all. Some may show it on the under hood sticker in the engine compartment. The best  and most reliable way to determine the exact amount of oil in the new car ac compressor is to drain the new ac compressor and measure the amount of oil if any,   inside.

Do you need assistance balancing the oil in your car ac compressor ?

Call Us today ! One of our  ASE certified car ac mechanics  will come to your home or office. We have car ac mechanics near you.

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